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Kechoindi S, Ben Yaghlane S, Mogren Al Mogren M, Bodi A, Hochlaf M. Photoelectron spectrum and breakdown diagram of ethanolamine: conformers, excited states, and thermochemistry. Phys Chem Chem Phys 2024; 26:24656-24666. [PMID: 39279722 DOI: 10.1039/d4cp03015j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/18/2024]
Abstract
Advanced theoretical methodologies and photoelectron photoion coincidence spectroscopy were used to investigate the photoionization of ethanolamine in the 8-18 eV energy range. We identified the low-lying cation conformers and the excited cation electronic states after vertical excitation from the most stable neutral conformer computationally. The TPES is composed of broad, structureless bands because of unfavorable Franck-Condon factors for origin transitions upon ionization, populating the D0-D7 cationic states from the most stable neutral conformer, g'Gg'. The adiabatic ionization energy of ethanolamine is calculated at 8.940 ± 0.010 eV, and the 0 K appearance energies of aminomethylium, NH2CH2+ (+CH2OH), and methyleneammonium, NH3CH2+ (+H2CO), are determined experimentally to be 9.708 ± 0.010 eV and 9.73 ± 0.03 eV, respectively. The former is used to re-evaluate the ethanolamine enthalpy of formation in the gas and liquid phases as ΔfH⊖298K[NH2(CH2)2OH, g] = -208.2 ± 1.2 kJ mol-1 and ΔfH⊖298K[NH2(CH2)2OH, l] = -267.8 ± 1.2 kJ mol-1. This represents a substantial correction of the previous experimental determination and is supported by ab initio calculations.
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Affiliation(s)
- S Kechoindi
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes 77454, Champs-sur-Marne, France.
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - S Ben Yaghlane
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - M Mogren Al Mogren
- Department of Chemistry, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - A Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, PSI, 5232, Villigen, Switzerland.
| | - M Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes 77454, Champs-sur-Marne, France.
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2
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Kats D, Christlmaier EMC, Schraivogel T, Alavi A. Orbital optimisation in xTC transcorrelated methods. Faraday Discuss 2024. [PMID: 39072553 DOI: 10.1039/d4fd00036f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
We present a combination of the bi-orthogonal orbital optimisation framework with the recently introduced xTC version of transcorrelation. This allows us to implement non-iterative perturbation based methods on top of the transcorrelated Hamiltonian. Additionally, the orbital optimisation influences results of other truncated methods, such as the distinguishable cluster with singles and doubles. The accuracy of these methods in comparison to standard xTC methods is demonstrated, and the advantages and disadvantages of the orbital optimisation are discussed.
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Affiliation(s)
- Daniel Kats
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany.
| | | | - Thomas Schraivogel
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany.
| | - Ali Alavi
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart, Germany.
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3
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Gasevic T, Bursch M, Ma Q, Grimme S, Werner HJ, Hansen A. The p-block challenge: assessing quantum chemistry methods for inorganic heterocycle dimerizations. Phys Chem Chem Phys 2024; 26:13884-13908. [PMID: 38661329 DOI: 10.1039/d3cp06217a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The elements of the p-block of the periodic table are of high interest in various chemical and technical applications like frustrated Lewis-pairs (FLP) or opto-electronics. However, high-quality benchmark data to assess approximate density functional theory (DFT) for their theoretical description are sparse. In this work, we present a benchmark set of 604 dimerization energies of 302 "inorganic benzenes" composed of all non-carbon p-block elements of main groups III to VI up to polonium. This so-called IHD302 test set comprises two classes of structures formed by covalent bonding and by weaker donor-acceptor (WDA) interactions, respectively. Generating reliable reference data with ab initio methods is challenging due to large electron correlation contributions, core-valence correlation effects, and especially the slow basis set convergence. To compute reference values for these dimerization reactions, after thorough testing, we applied a computational protocol using state-of-the-art explicitly correlated local coupled cluster theory termed PNO-LCCSD(T)-F12/cc-VTZ-PP-F12(corr.). It includes a basis set correction at the PNO-LMP2-F12/aug-cc-pwCVTZ level. Based on these reference data, we assess 26 DFT methods in combination with three different dispersion corrections and the def2-QZVPP basis set, five composite DFT approaches, and five semi-empirical quantum mechanical methods. For the covalent dimerizations, the r2SCAN-D4 meta-GGA, the r2SCAN0-D4 and ωB97M-V hybrids, and the revDSD-PBEP86-D4 double-hybrid functional are found to be the best-performing methods among the evaluated functionals of the respective class. However, since def2 basis sets for the 4th period are not associated to relativistic pseudo-potentials, we obtained significant errors in the covalent dimerization energies (up to 6 kcal mol-1) for molecules containing p-block elements of the 4th period. Significant improvements were achieved for systems containing 4th row elements by using ECP10MDF pseudopotentials along with re-contracted aug-cc-pVQZ-PP-KS basis sets introduced in this work with the contraction coefficients taken from atomic DFT (PBE0) calculations. Overall, the IHD302 set represents a challenge to contemporary quantum chemical methods. This is due to a large number of spatially close p-element bonds which are underrepresented in other benchmark sets, and the partial covalent bonding character for the WDA interactions. The IHD302 set may be helpful to develop more robust and transferable approximate quantum chemical methods in the future.
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Affiliation(s)
- Thomas Gasevic
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4, 53115 Bonn, Germany.
| | - Markus Bursch
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
- FACCTs GmbH, 50677, Koeln, Germany
| | - Qianli Ma
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4, 53115 Bonn, Germany.
| | - Hans-Joachim Werner
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, Beringstr. 4, 53115 Bonn, Germany.
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Xue Y, Sexton TM, Yang J, Tschumper GS. Systematic analysis of electronic barrier heights and widths for concerted proton transfer in cyclic hydrogen bonded clusters: (HF) n, (HCl) n and (H 2O) n where n = 3, 4, 5. Phys Chem Chem Phys 2024; 26:12483-12494. [PMID: 38619858 DOI: 10.1039/d4cp00422a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The MP2 and CCSD(T) methods are paired with correlation consistent basis sets as large as aug-cc-pVQZ to optimize the structures of the cyclic minima for (HF)n, (HCl)n and (H2O)n where n = 3-5, as well as the corresponding transition states (TSs) for concerted proton transfer (CPT). MP2 and CCSD(T) harmonic vibrational frequencies confirm the nature of each minimum and TS. Both conventional and explicitly correlated CCSD(T) computations are employed to assess the electronic dissociation energies and barrier heights for CPT near the complete basis (CBS) limit for all 9 clusters. Results for (HF)n are consistent with prior studies identifying Cnh and Dnh point group symmetry for the minima and TSs, respectively. Our computations also confirm that CPT proceeds through Cs TS structures for the C1 minima of (H2O)3 and (H2O)5, whereas the process goes through a TS with D2d symmetry for the S4 global minimum of (H2O)4. This work corroborates earlier findings that the minima for (HCl)3, (HCl)4 and (HCl)5 have C3h, S4 and C1 point group symmetry, respectively, and that the Cnh structures are not minima for n = 4 and 5. Moreover, our computations show the TSs for CPT in (HCl)3, (HCl)4 and (HCl)5 have D3h, D2d, and C2 point group symmetry, respectively. At the CCSD(T) CBS limit, (HF)4 and (HF)5 have the smallest electronic barrier heights for CPT (≈15 kcal mol-1 for both), followed by the HF trimer (≈21 kcal mol-1). The barriers are appreciably higher for the other clusters (around 27 kcal mol-1 for (H2O)4 and (HCl)3; roughly 30 kcal mol-1 for (H2O)3, (H2O)5 and (HCl)4; up to 38 kcal mol-1 for (HCl)5). At the CBS limit, MP2 significantly underestimates the CCSD(T) barrier heights (e.g., by ca. 2, 4 and 7 kcal mol-1 for the pentamers of HF, H2O and HCl, respectively), whereas CCSD overestimates these barriers by roughly the same magnitude. Scaling the barrier heights and dissociation energies by the number of fragments in the cluster reveals strong linear relationships between the two quantities and with the magnitudes of the imaginary vibrational frequency for the TSs.
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Affiliation(s)
- Yuan Xue
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677-1848, USA.
| | - Thomas More Sexton
- School of Arts and Sciences, Chemistry University of Mary, Bismark, ND 58504, USA.
| | - Johnny Yang
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677-1848, USA.
| | - Gregory S Tschumper
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677-1848, USA.
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De Vos J, Schröder B, Rauhut G. Comprehensive quantum chemical analysis of the (ro)vibrational spectrum of thiirane and its deuterated isotopologue. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 302:123083. [PMID: 37423098 DOI: 10.1016/j.saa.2023.123083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/11/2023]
Abstract
The (ro)vibrational spectra of thiirane, c-C2H4S, and its fully deuterated isotopologue, c-C2D4S, have been studied by means of vibrational configuration interaction theory, VCI, its incremental variant, iVCI, and subsequent variational rovibrational calculations, RVCI, which rely on multidimensional potential energy surfaces of coupled-cluster quality including up to four-mode coupling terms. Accurate geometrical parameters, fundamental vibrational transitions and first overtones, rovibrational spectra and rotational spectroscopic constants have been determined from these calculations and were compared with experimental results whenever available. A number of tentative misassignments in the vibrational spectra could be resolved and most results for the deuterated thiirane are high-level predictions, which may guide experiments to come. Besides this, a new implementation of infrared intensities within the iVCI framework has been tested for the transitions of the title compounds and are compared with results obtained from standard VCI calculations.
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Affiliation(s)
- John De Vos
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany; Department of Chemistry, Ghent University, Krijgslaan 281, 9000, Ghent, Belgium.
| | - Benjamin Schröder
- Institute for Physical Chemistry, University of Göttingen, Tammannstr. 6, 37077, Göttingen, Germany.
| | - Guntram Rauhut
- Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
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Yu H, Møller KH, Buenconsejo RS, Crounse JD, Kjaergaard HG, Wennberg PO. Atmospheric Photo-Oxidation of 2-Ethoxyethanol: Autoxidation Chemistry of Glycol Ethers. J Phys Chem A 2023; 127:9564-9579. [PMID: 37934888 DOI: 10.1021/acs.jpca.3c04456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
We investigate the gas-phase photo-oxidation of 2-ethoxyethanol (2-EE) initiated by the OH radical with a focus on its autoxidation pathways. Gas-phase autoxidation─intramolecular H-shifts followed by O2 addition─has recently been recognized as a major atmospheric chemical pathway that leads to the formation of highly oxygenated organic molecules (HOMs), which are important precursors for secondary organic aerosols (SOAs). Here, we examine the gas-phase oxidation pathways of 2-EE, a model compound for glycol ethers, an important class of volatile organic compounds (VOCs) used in volatile chemical products (VCPs). Both experimental and computational techniques are applied to analyze the photochemistry of the compound. We identify oxidation products from both bimolecular and autoxidation reactions from chamber experiments at varied HO2 levels and provide estimations of rate coefficients and product branching ratios for key reaction pathways. The H-shift processes of 2-EE peroxy radicals (RO2) are found to be sufficiently fast to compete with bimolecular reactions under modest NO/HO2 conditions. More than 30% of the produced RO2 are expected to undergo at least one H-shift for conditions typical of modern summer urban atmosphere, where RO2 bimolecular lifetime is becoming >10 s, which implies the potential for glycol ether oxidation to produce considerable amounts of HOMs at reduced NOx levels and elevated temperature. Understanding the gas-phase autoxidation of glycol ethers can help fill the knowledge gap in the formation of SOA derived from oxygenated VOCs emitted from VCP sources.
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Affiliation(s)
- Hongmin Yu
- Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, United States
| | - Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Reina S Buenconsejo
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, United States
| | - John D Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, United States
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Paul O Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, United States
- Division of Engineering and Applied Science, California Institute of Technology, 1200 E California Blvd., Pasadena, California 91125, United States
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7
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Kjærgaard ER, Møller KH, Kjaergaard HG. Atmospheric Oxidation of Hydroperoxy Amides. J Phys Chem A 2023; 127:9311-9321. [PMID: 37877667 DOI: 10.1021/acs.jpca.3c04509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Recently, hydroperoxy amides were identified as major products of OH-initiated autoxidation of tertiary amines in the atmosphere. The formation mechanism is analogous to that found for ethers and sulfides but substantially faster. However, the atmospheric fate of the hydroperoxy amides remains unknown. Using high-level theoretical methods, we study the most likely OH-initiated oxidation pathways of the hydroperoxy and dihydroperoxy amides derived from trimethylamine autoxidation. Overall, we find that the OH-initiated oxidation of the hydroperoxy amides predominantly leads to the formation of imides under NO-dominated conditions and more highly oxidized hydroperoxy amides under HO2-dominated conditions. Unimolecular reactions are found to be surprisingly slow, likely due to the restricting, planar structure of the amide moiety.
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Affiliation(s)
- Eva R Kjærgaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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8
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Ten-No SL. Nonunitary projective transcorrelation theory inspired by the F12 ansatz. J Chem Phys 2023; 159:171103. [PMID: 37921247 DOI: 10.1063/5.0175337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023] Open
Abstract
An alternative nonunitary transcorrelation, inspired by the F12 ansatz, is investigated. In contrast to the Jastrow transcorrelation of Boys-Handy, the effective Hamiltonian of this projective transcorrelation features: 1. a series terminating formally at four-body interactions. 2. no spin-contamination within the non-relativistic framework. 3. simultaneous satisfaction of the singlet and triplet first-order cusp conditions. 4. arbitrary choices of pairs for correlation including frozen-core approximations. We discuss the connection between the projective transcorrelation and F12 theory with applications to small molecules, to show that the cusp conditions play an important role to reduce the uncertainty arising from the nonunitary transformation.
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Affiliation(s)
- Seiichiro L Ten-No
- Graduate School of System Informatics, Kobe University, Nada-ku, Kobe 657-8501, Japan
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Werner HJ, Hansen A. Accurate Calculation of Isomerization and Conformational Energies of Larger Molecules Using Explicitly Correlated Local Coupled Cluster Methods in Molpro and ORCA. J Chem Theory Comput 2023; 19:7007-7030. [PMID: 37486154 DOI: 10.1021/acs.jctc.3c00270] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
An overview of the approximations in the explicitly correlated local coupled cluster methods PNO-LCCSD(T)-F12 in Molpro and DLPNO-CCSD(T)F12 in ORCA is given. Options to select the domains of projected atomic orbitals (PAOs), pair natural orbitals (PNOs), and triples natural orbitals (TNOs) in both programs are described and compared in detail. The two programs are applied to compute isomerization and conformational energies of the ISOL24 and ACONFL test sets, where the former is part of the GMTKN55 benchmark suite. Thorough studies of basis set effects are presented for selected systems. These revealed large intramolecular basis set superposition effects that make it practically impossible to reliably determine the complete basis set (CBS) limits without including explicitly correlated terms. The latter strongly reduce the basis set dependence and at the same time also errors caused by the local domain approximations. On the basis of these studies, the PNO-LCCSD(T)-F12 method is applied to determine new reference energies for the above-mentioned benchmark sets. We are confident that our results should agree within a few tenths of a kcal mol-1 with the (unknown) CCSD(T)/CBS values, which therefore allowed us to define computational settings for accurate explicitly correlated local coupled cluster methods with moderate computational effort. With these protocols, especially PNO-LCCSD(T)-F12b/AVTZ', reliable reference values for comprehensive benchmark sets can be generated efficiently. This can significantly advance the development and evaluation of the performance of approximate electronic structure methods, especially improved density functional approximations or machine learning approaches.
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Affiliation(s)
- Hans-Joachim Werner
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, Universität Bonn, Beringstrasse 4, D-53115 Bonn, Germany
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10
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Ashani MN, Huang Q, Flowers AM, Brown A, Aerts A, Otero-de-la-Roza A, DiLabio GA. Accurate Potential Energy Surfaces Using Atom-Centered Potentials and Minimal High-Level Data. J Phys Chem A 2023; 127:8015-8024. [PMID: 37712536 DOI: 10.1021/acs.jpca.3c04558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
We demonstrate that a Δ-density functional theory (Δ-DFT) approach based on atom-centered potentials (ACPs) represents a computationally inexpensive and accurate method for representing potential energy surfaces (PESs) for the HONO and HFCO molecules and vibrational frequencies derived therefrom. Using as few as 100 CCSD(T)-F12a reference energies, ACPs developed for use with B3LYP/def2-TZVPP are shown to produce PESs for HONO and HFCO with mean absolute errors of 27.7 and 5.8 cm-1, respectively. Application of the multiconfigurational time-dependent Hartree (MCTDH) method with ACP-corrected B3LYP/def2-TZVPP PESs produces vibrational frequencies for cis- and trans-HONO with mean absolute percent errors (MAPEs) of 0.8 and 1.1, compared to 0.8 obtained for the two isomers with CCSD(T)-F12a/cc-pVTZ-F12/MCTDH. For HFCO, the vibrational frequencies obtained using the present (Δ-DFT)/MCTDH approach give a MAPE of 0.1, which is the error obtained with CCSD(T)-F12a/cc-pVTZ-F12/MCTDH. The ACP approach is therefore successful in representing a PES calculated at a high level of theory (CCSD(T)-F12a) and a promising method for the development of a general protocol for the representation of accurate molecular PESs and the calculation of molecular properties from them.
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Affiliation(s)
- Mahsa Nazemi Ashani
- Department of Chemistry, University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - Qinan Huang
- Department of Chemistry, University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
| | - A Mackenzie Flowers
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Alex Brown
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - Antoine Aerts
- Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), Université libre de Bruxelles, 50 avenue F. Roosevelt, C.P. 160/09, B-1050 Brussels, Belgium
| | - Alberto Otero-de-la-Roza
- Departamento de Química Física y Analítica and MALTA Consolider Team, Facultad de Química, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Gino A DiLabio
- Department of Chemistry, University of British Columbia, 3247 University Way, Kelowna, British Columbia V1V 1V7, Canada
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Yang J, Cong Y, Li Y, Li H. Machine Learning Approach Based on a Range-Corrected Deep Potential Model for Efficient Vibrational Frequency Computation. J Chem Theory Comput 2023; 19:6366-6374. [PMID: 37652890 DOI: 10.1021/acs.jctc.3c00386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
As an ensemble average result, vibrational spectrum simulation can be time-consuming with high accuracy methods. We present a machine learning approach based on the range-corrected deep potential (DPRc) model to improve the computing efficiency. The DPRc method divides the system into "probe region" and "solvent region"; "solvent-solvent" interactions are not counted in the neural network. We applied the approach to two systems: formic acid C═O stretching and MeCN C≡N stretching vibrational frequency shifts in water. All data sets were prepared using the quantum vibration perturbation approach. Effects of different region divisions, one-body correction, cut range, and training data size were tested. The model with a single-molecule "probe region" showed stable accuracy; it ran roughly 10 times faster than regular deep potential and reduced the training time by about four. The approach is efficient, easy to apply, and extendable to calculating various spectra.
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Affiliation(s)
- Jitai Yang
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Yang Cong
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - You Li
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
| | - Hui Li
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023, P. R. China
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12
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Wang Z, Hu X, Xue X, Zhou S, Li X, Yang Y, Zhou J, Shu Z, Zhao B, Yu X, Gong M, Wang Z, Ma P, Wu Y, Chen X, Wang J, Ren X, Wang C, Ding D. Directly imaging excited state-resolved transient structures of water induced by valence and inner-shell ionisation. Nat Commun 2023; 14:5420. [PMID: 37669964 PMCID: PMC10480213 DOI: 10.1038/s41467-023-41204-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/24/2023] [Indexed: 09/07/2023] Open
Abstract
Real-time imaging of transient structure of the electronic excited state is fundamentally critical to understand and control ultrafast molecular dynamics. The ejection of electrons from the inner-shell and valence level can lead to the population of different excited states, which trigger manifold ultrafast relaxation processes, however, the accurate imaging of such electronic state-dependent structural evolutions is still lacking. Here, by developing the laser-induced electron recollision-assisted Coulomb explosion imaging approach and molecular dynamics simulations, snapshots of the vibrational wave-packets of the excited (A) and ground states (X) of D2O+ are captured simultaneously with sub-10 picometre and few-femtosecond precision. We visualise that θDOD and ROD are significantly increased by around 50∘ and 10 pm, respectively, within approximately 8 fs after initial ionisation for the A state, and the ROD further extends 9 pm within 2 fs along the ground state of the dication in the present condition. Moreover, the ROD can stretch more than 50 pm within 5 fs along autoionisation state of dication. The accuracies of the results are limited by the simulations. These results provide comprehensive structural information for studying the fascinating molecular dynamics of water, and pave the way towards to make a movie of excited state-resolved ultrafast molecular dynamics and light-induced chemical reaction.
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Affiliation(s)
- Zhenzhen Wang
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Xiaoqing Hu
- Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, 100088, Beijing, China
| | - Xiaorui Xue
- School of Physics, Xi'an Jiaotong University, 710049, Xi'an, China
| | - Shengpeng Zhou
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Xiaokai Li
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Yizhang Yang
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Jiaqi Zhou
- School of Physics, Xi'an Jiaotong University, 710049, Xi'an, China
| | - Zheng Shu
- Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, 100088, Beijing, China
| | - Banchi Zhao
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Xitao Yu
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Maomao Gong
- Hefei National Research Center for Physical Sciences at Microscale and Department of Modern Physic, University of Science and Technology of China, 230026, Hefei, China
- School of Physics and Information Technology, Shaanxi Normal University, 710119, Xi' an, China
| | - Zhenpeng Wang
- Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, 100088, Beijing, China
- Hefei National Research Center for Physical Sciences at Microscale and Department of Modern Physic, University of Science and Technology of China, 230026, Hefei, China
| | - Pan Ma
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China
| | - Yong Wu
- Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, 100088, Beijing, China.
- HEDPS, Center of Applied Physics and Technology, Peking University, 100871, Beijing, China.
| | - Xiangjun Chen
- Hefei National Research Center for Physical Sciences at Microscale and Department of Modern Physic, University of Science and Technology of China, 230026, Hefei, China
| | - Jianguo Wang
- Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, 100088, Beijing, China
| | - Xueguang Ren
- School of Physics, Xi'an Jiaotong University, 710049, Xi'an, China.
| | - Chuncheng Wang
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China.
| | - Dajun Ding
- Institute of Atomic and Molecular Physics and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, 130012, Changchun, China.
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13
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Artiukhin DG, Godtliebsen IH, Schmitz G, Christiansen O. Gaussian process regression adaptive density-guided approach: Toward calculations of potential energy surfaces for larger molecules. J Chem Phys 2023; 159:024102. [PMID: 37428042 DOI: 10.1063/5.0152367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/15/2023] [Indexed: 07/11/2023] Open
Abstract
We present a new program implementation of the Gaussian process regression adaptive density-guided approach [Schmitz et al., J. Chem. Phys. 153, 064105 (2020)] for automatic and cost-efficient potential energy surface construction in the MidasCpp program. A number of technical and methodological improvements made allowed us to extend this approach toward calculations of larger molecular systems than those previously accessible and maintain the very high accuracy of constructed potential energy surfaces. On the methodological side, improvements were made by using a Δ-learning approach, predicting the difference against a fully harmonic potential, and employing a computationally more efficient hyperparameter optimization procedure. We demonstrate the performance of this method on a test set of molecules of growing size and show that up to 80% of single point calculations could be avoided, introducing a root mean square deviation in fundamental excitations of about 3 cm-1. A much higher accuracy with errors below 1 cm-1 could be achieved with tighter convergence thresholds still reducing the number of single point computations by up to 68%. We further support our findings with a detailed analysis of wall times measured while employing different electronic structure methods. Our results demonstrate that GPR-ADGA is an effective tool, which could be applied for cost-efficient calculations of potential energy surfaces suitable for highly accurate vibrational spectra simulations.
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Affiliation(s)
- Denis G Artiukhin
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany
| | - Ian H Godtliebsen
- Department of Chemistry, Aarhus Universitet, DK-8000 Aarhus, Denmark
| | - Gunnar Schmitz
- Lehrstuhl für Theoretische Chemie II, Ruhr-Universität Bochum, Universitätstraße 150, 44801 Bochum, Germany
| | - Ove Christiansen
- Department of Chemistry, Aarhus Universitet, DK-8000 Aarhus, Denmark
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14
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Barone V, Fusè M, Aguado R, Potenti S, León I, Alonso ER, Mata S, Lazzari F, Mancini G, Spada L, Gualandi A, Cozzi PG, Puzzarini C, Alonso JL. Bringing Machine-Learning Enhanced Quantum Chemistry and Microwave Spectroscopy to Conformational Landscape Exploration: the Paradigmatic Case of 4-Fluoro-Threonine. Chemistry 2023; 29:e202203990. [PMID: 36734519 DOI: 10.1002/chem.202203990] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/02/2023] [Indexed: 02/04/2023]
Abstract
A combined experimental and theoretical study has been carried out on 4-fluoro-threonine, the only naturally occurring fluorinated amino acid. Fluorination of the methyl group significantly increases the conformational complexity with respect to the parent amino acid threonine. The conformational landscape has been characterized in great detail, with special attention given to the inter-conversion pathways between different conformers. This led to the identification of 13 stable low-energy minima. The equilibrium population of so many conformers produces a very complicated and congested rotational spectrum that could be assigned through a strategy that combines several levels of quantum chemical calculations with the principles of machine learning. Twelve conformers out of 13 could be experimentally characterized. The results obtained from the analysis of the intra-molecular interactions can be exploited to accurately model fluorine-substitution effects in biomolecules.
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Affiliation(s)
- V Barone
- SMART Laboratory, Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - M Fusè
- SMART Laboratory, Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - R Aguado
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia Parque Cientifico UVa, Universidad de Valladolid, 47005, Valladolid, Spain
| | - S Potenti
- SMART Laboratory, Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126, Pisa, Italy
- Dipartimento di "Chimica Giacomo Ciamician", University of Bologna, via F. Selmi 2, 40126, Bologna, Italy
| | - I León
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia Parque Cientifico UVa, Universidad de Valladolid, 47005, Valladolid, Spain
| | - E R Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia Parque Cientifico UVa, Universidad de Valladolid, 47005, Valladolid, Spain
| | - S Mata
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia Parque Cientifico UVa, Universidad de Valladolid, 47005, Valladolid, Spain
| | - F Lazzari
- SMART Laboratory, Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - G Mancini
- SMART Laboratory, Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - L Spada
- SMART Laboratory, Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - A Gualandi
- Dipartimento di "Chimica Giacomo Ciamician", University of Bologna, via F. Selmi 2, 40126, Bologna, Italy
| | - P G Cozzi
- Dipartimento di "Chimica Giacomo Ciamician", University of Bologna, via F. Selmi 2, 40126, Bologna, Italy
| | - C Puzzarini
- Dipartimento di "Chimica Giacomo Ciamician", University of Bologna, via F. Selmi 2, 40126, Bologna, Italy
| | - J L Alonso
- Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia Parque Cientifico UVa, Universidad de Valladolid, 47005, Valladolid, Spain
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15
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Barone V, Fusè M, Lazzari F, Mancini G. Benchmark Structures and Conformational Landscapes of Amino Acids in the Gas Phase: A Joint Venture of Machine Learning, Quantum Chemistry, and Rotational Spectroscopy. J Chem Theory Comput 2023; 19:1243-1260. [PMID: 36731119 PMCID: PMC9979611 DOI: 10.1021/acs.jctc.2c01143] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The accurate characterization of prototypical bricks of life can strongly benefit from the integration of high resolution spectroscopy and quantum mechanical computations. We have selected a number of representative amino acids (glycine, alanine, serine, cysteine, threonine, aspartic acid and asparagine) to validate a new computational setup rooted in quantum-chemical computations of increasing accuracy guided by machine learning tools. Together with low-lying energy minima, the barriers ruling their interconversion are evaluated in order to unravel possible fast relaxation paths. Vibrational and thermal effects are also included in order to estimate relative free energies at the temperature of interest in the experiment. The spectroscopic parameters of all the most stable conformers predicted by this computational strategy, which do not have low-energy relaxation paths available, closely match those of the species detected in microwave experiments. Together with their intrinsic interest, these accurate results represent ideal benchmarks for more approximate methods.
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Affiliation(s)
- Vincenzo Barone
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy,
| | - Marco Fusè
- DMMT-sede
Europa, Universitá di Brescia, viale Europa 11, 25121 Brescia, Italy
| | - Federico Lazzari
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Giordano Mancini
- Scuola
Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy
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16
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Schneider M, Rauhut G. Quantum chemical rovibrational analysis of aminoborane and its isotopologues. J Comput Chem 2023; 44:298-306. [PMID: 35582830 DOI: 10.1002/jcc.26893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/22/2022] [Accepted: 04/28/2022] [Indexed: 12/31/2022]
Abstract
Aminoborane, H2 NBH2 and its isotopologues, H2 N10 BH2 , D2 NBD2 , and D2 N10 BD2 , have been studied by high-level ab initio methods. All calculations rely on multidimensional potential energy surfaces and dipole moment surfaces including high-order mode coupling terms, which have been obtained from electronic structure calculations at the level of explicitly correlated coupled-cluster theory, CCSD(T)-F12, or the distinguishable cluster approximation, DCSD. Subsequent vibrational structure calculations based on second-order vibrational perturbation theory, VPT2, and vibrational configuration interaction theory, VCI, were used to determine rotational constants, centrifugal distortion constants, vibrationally averaged geometrical parameters and (an)harmonic vibrational frequencies. The impact of core-correlation effects is discussed in detail. Rovibrational VCI calculations were used to simulate the gas phase spectra of these species and an in-depth analysis of the ν7 band of aminoborane is provided. Color-coding is used to reveal the identity of the individual progressions of the rovibrational transitions for this particular mode.
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Affiliation(s)
- Moritz Schneider
- Institute for Theoretical Chemistry, University of Stuttgart, Stuttgart, Germany
| | - Guntram Rauhut
- Institute for Theoretical Chemistry, University of Stuttgart, Stuttgart, Germany
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17
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Lülf S, Guo L, Parchomyk T, Harvey JN, Koszinowski K. Microscopic Reactivity of Phenylferrate Ions toward Organyl Halides. Chemistry 2022; 28:e202202030. [PMID: 35948515 PMCID: PMC9826238 DOI: 10.1002/chem.202202030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Indexed: 01/11/2023]
Abstract
Despite its practical importance, organoiron chemistry remains poorly understood due to its mechanistic complexity. Here, we focus on the oxidative addition of organyl halides to phenylferrate anions in the gas phase. By mass-selecting individual phenylferrate anions, we can determine the effect of the oxidation state, the ligation, and the nuclearity of the iron complex on its reactions with a series of organyl halides RX. We find that Ph2 Fe(I)- and other low-valent ferrates are more reactive than Ph3 Fe(II)- ; Ph4 Fe(III)- is inert. The coordination of a PPh3 ligand or the presence of a second iron center lower the reactivity. Besides direct cross-coupling reactions resulting in the formation of RPh, we also observe the abstraction of halogen atoms. This reaction channel shows the readiness of organoiron species to undergo radical-type processes. Complementary DFT calculations afford further insight and rationalize the high reactivity of the Ph2 Fe(I)- complex by the exothermicity of the oxidative addition and the low barriers associated with this reaction step. At the same time, they point to the importance of changes of the spin state in the reactions of Ph3 Fe(II)- .
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Affiliation(s)
- Stefan Lülf
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstr. 237077GöttingenGermany
| | - Luxuan Guo
- Department of ChemistryKU LeuvenCelestijnenlaan 200FB-3001LeuvenBelgium
| | - Tobias Parchomyk
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstr. 237077GöttingenGermany
| | - Jeremy N. Harvey
- Department of ChemistryKU LeuvenCelestijnenlaan 200FB-3001LeuvenBelgium
| | - Konrad Koszinowski
- Institut für Organische und Biomolekulare ChemieUniversität GöttingenTammannstr. 237077GöttingenGermany
- Wöhler Research Institute for Sustainable ChemistryUniversität GöttingenTammannstr. 237077GöttingenGermany
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18
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León I, Fusè M, Alonso ER, Mata S, Mancini G, Puzzarini C, Alonso JL, Barone V. Unbiased disentanglement of conformational baths with the help of microwave spectroscopy, quantum chemistry and artificial intelligence: the puzzling case of homocysteine. J Chem Phys 2022; 157:074107. [DOI: 10.1063/5.0102841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An integrated experimental-computational strategy for the accurate characterization of the conformational landscape of flexible biomolecule building blocks is proposed. This is based on the combination of rotational spectroscopy with quantum-chemical computations guided by artificial intelligence tools. The first step of the strategy is the conformer search and relative stability evaluation performed by means of an evolutionary algorithm. In this step, last generation semiempirical methods are exploited together with hybrid and double-hybrid density functionals. Next, the barriers ruling the interconversion between the low-lying conformers are evaluated in order to unravel possible fast relaxation paths. The relative stabilities and spectroscopic parameters of the ``surviving' conformers are then refined using state-of-the-art composite schemes. The reliability of the computational procedure is further improved by the inclusion of vibrational and thermal effects. The final step of the strategy is the comparison between experiment and theory without any ad hoc adjustment, which allows an unbiased assignment of the spectroscopic features in terms of different conformers and their spectroscopic parameters. The proposed approach has been tested and validated for homocysteine, a highly flexible non-proteinogenic alpha-amino acid. The synergism of the integrated strategy allowed the characterization of five conformers stabilized by bifurcated N-H-O=C hydrogen bonds, together with an additional conformer involving a more conventional HNH-O hydrogen bond. The stability order estimated from the experimental intensities as well as the number and type of conformers observed in the gas phase are in full agreement with the theoretical predictions. Analogously, a good match has been found for the spectroscopic parameters.
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Affiliation(s)
- Iker León
- Universidad de Valladolid - Campus Miguel Delibes, Spain
| | | | - Elena R. Alonso
- Química Física y Química Inorgánica, Universidad de Valladolid, Spain
| | - Santiago Mata
- Grupo de Espectroscopia Molecular (GEM). Edificio Quifima. Laboratorios de Espectroscopia y Bioespectroscopia. Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, Spain
| | | | | | - Jose L. Alonso
- Grupo de Espectroscopia Molecular (GEM). Edificio Quifima. Laboratorios de Espectroscopia y Bioespectroscopia, Universidad de Valladolid Departamento Química Física y Química Inorgánica, Spain
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19
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Bourgalais J, Jiang Z, Bloino J, Herbinet O, Carstensen HH, Garcia GA, Arnoux P, Tran LS, Vanhove G, Nahon L, Battin-Leclerc F, Hochlaf M. Accounting for molecular flexibility in photoionization: case of tert-butyl hydroperoxide. Phys Chem Chem Phys 2022; 24:10826-10837. [PMID: 35485277 DOI: 10.1039/d2cp00929c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
tert-Butyl hydroperoxide (tBuOOH) is a common intermediate in the oxidation of organic compounds that needs to be accurately quantified in complex gas mixtures for the development of chemical kinetic models of low temperature combustion. This work presents a combined theoretical and experimental investigation on the synchrotron-based VUV single photon ionization of gas-phase tBuOOH in the 9.0 - 11.0 eV energy range, including dissociative ionization processes. Computations consist of the determination of the structures, vibrational frequencies and the energetics of neutral and ionic tBuOOH. The Franck-Condon spectrum for the tBuOOH+ (X+) + e- ← tBuOOH (X) + hν transition is computed, where special treatment is undertaken because of the flexibility of tBuOOH, in particular regarding the OOH group. Through comparison of the experimental mass-selected threshold photoelectron spectra with explicitly correlated coupled cluster calculations and Franck-Condon simulations that account for the flexibility of the molecule, an estimation of the ionization energy is given. The appearance energy of the only fragment observed within the above-mentioned energy range, identified as the tert-butyl C4H9+, is also reported. Finally, the signal branching ratio between the parent and the fragment ions is provided as a function of photon energy, essential to quantify tBuOOH in gas-phase oxidation/combustion experiments via advanced mass spectrometry techniques.
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Affiliation(s)
| | | | - Julien Bloino
- SMART Laboratory, Scuola Normale Superiore, Pisa, Italy
| | | | - Hans-Heinrich Carstensen
- Thermochemical Processes Group (GPT), Department of Chemical and Environmental Engineering, Engineering and Architecture School, University of Zaragoza, Spain.,Fundacion Agencia Aragonesa para la Investigacion y el Desarrollo (ARAID), Zagaroza, Spain
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, 91192 Gif-sur-Yvette Cedex, France
| | | | - Luc-Sy Tran
- PC2A, Université de Lille, CNRS, Avenue Mendeleiev, 59650 Villeneuve-d'Ascq, France
| | - Guillaume Vanhove
- PC2A, Université de Lille, CNRS, Avenue Mendeleiev, 59650 Villeneuve-d'Ascq, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, 91192 Gif-sur-Yvette Cedex, France
| | | | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs sur Marne, France.
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20
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Aerts A, Schaefer MR, Brown A. Adaptive Fitting of Potential Energy Surfaces of Small to Medium-Sized Molecules in Sum-of-Product Form: Application to Vibrational Spectroscopy. J Chem Phys 2022; 156:164106. [DOI: 10.1063/5.0089570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A semi-automatic sampling and fitting procedure for generating sum-of-product (Born-Oppenheimer) potential energy surfaces based on a high-dimensional model representation is presented. The adaptive sampling procedure and subsequent fitting relies on energies only and can be used for re-fitting existing analytic potential energy surfaces in sum-of-product form or for direct fits from ab initio computa- tions. The method is tested by fitting ground electronic state potential energy surfaces for small to medium sized semi-rigid molecules, i.e., HFCO, HONO, and HCOOH, based upon ab initio computations at the CCSD(T)-F12/cc-pVTZ-F12 or MP2/aug-cc-pVTZ levels of theory. Vibrational eigenstates are computed using block improved relaxation in the Heidelberg MCTDH package and compared to available experimental and theoretical data. The new potential energy surfaces are compared to the best ones currently available for these molecules, in terms of accuracy, including of resulting vibrational states, required numbers of sampling points, and number of fitting parameters. The present procedure leads to compact expansions and scales well with the number of dimensions for simple potentials such as single or double wells.
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Affiliation(s)
| | | | - Alex Brown
- Department of Chemistry, University of Alberta, Canada
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21
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Xu S, Liang J, Cao S, He R, Yin G, Wang QD. A Hierarchical Theoretical Study of the Hydrogen Abstraction Reactions of H 2/C 1-C 4 Molecules by the Methyl Peroxy Radical and Implications for Kinetic Modeling. ACS OMEGA 2022; 7:8675-8685. [PMID: 35309437 PMCID: PMC8928341 DOI: 10.1021/acsomega.1c06683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
The hydrogen atom abstraction by the methyl peroxy radical (CH3O2) is an important reaction class in detailed chemical kinetic modeling of the autoignition properties of hydrocarbon fuels. Systematic theoretical studies are performed on this reaction class for H2/C1-C4 fuels, which is critical in the development of a base model for large fuels. The molecules include hydrogen, alkanes, alkenes, and alkynes with a carbon number from 1 to 4. The B2PLYP-D3/cc-pVTZ level of theory is employed to optimize the geometries of all of the reactants, transition states, and products and also the treatments of hindered rotation for lower frequency modes. Accurate benchmark calculations for abstraction reactions of hydrogen, methane, and ethylene with CH3O2 are performed by using the coupled cluster method with explicit inclusion of single and double electron excitations and perturbative inclusion of triple electron excitations (CCSD(T)), the domain-based local pair-natural orbital coupled cluster method (DLPNO-CCSD(T)), and the explicitly correlated CCSD(T)-F12 method with large basis sets. Reaction rate constants are computed via conventional transition state theory with quantum tunneling corrections. The computed rate constants are compared with literature values and those employed in detailed chemical kinetic mechanisms. The calculated rate constants are implemented into the recently developed NUIGMECH1.1 base model for kinetic modeling of ignition properties.
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Affiliation(s)
- Shenying Xu
- Faculty
of Materials and Chemical Engineering, Yibin
University, Yibin, Sichuan 644000, People’s Republic of China
| | - Jinhu Liang
- Faculty
of Materials and Chemical Engineering, Yibin
University, Yibin, Sichuan 644000, People’s Republic of China
- School
of Environment and Safety Engineering, North
University of China, Taiyuan 030051, People’s Republic
of China
| | - Shutong Cao
- School
of Environment and Safety Engineering, North
University of China, Taiyuan 030051, People’s Republic
of China
| | - Ruining He
- School
of Environment and Safety Engineering, North
University of China, Taiyuan 030051, People’s Republic
of China
| | - Guoliang Yin
- Faculty
of Materials and Chemical Engineering, Yibin
University, Yibin, Sichuan 644000, People’s Republic of China
| | - Quan-De Wang
- Jiangsu
Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization,
Low Carbon Energy Institute, China University
of Mining and Technology, Xuzhou 221008, People’s Republic
of China
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22
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Bader F, Tremblay JC, Paulus B. Theoretical modeling of molecules in weakly interacting environments: trifluoride anions in argon. Phys Chem Chem Phys 2022; 24:3555-3567. [PMID: 35080559 DOI: 10.1039/d1cp02338a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The properties of molecules can be affected by the presence of a host environment. Even in inert rare gas matrices such effects are observable, as for instance in matrix isolation spectroscopy. In this work we study the trifluoride anion in cryogenic argon environments. To investigate the structure and vibrational properties of the guest-host systems, a potential energy surface of compound F-3-argon structures is determined from ab initio calculations with the CCSD(T)-F12b approach. Argon environments are probed with minima hopping optimizations of extended trifluoride-argon clusters. The vibrations of F-3 within the optimized environments are examined with anharmonic vibrational analyses. Among the three identified structural surroundings for the trifluoride, two are characterized by relatively favorable guest-host and host-host interactions as well as vibrational zero-point energies. A striking dependence of the trifluoride properties on the particular argon environment reveals the delicate influence of the host atoms on the guest molecule. Very good agreement with measured data suggests that in experiment F-3 occupies a double-vacancy site.
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Affiliation(s)
- Frederik Bader
- Institut für Chemie und Biochemie, Freie Universität Berlin, D-14195, Berlin, Germany.
| | - Jean Christophe Tremblay
- Laboratoire de Physique et Chimie Théoriques, CNRS-Université de Lorraine, UMR 7019, ICPM, 1Bd Arago, 57070 Metz, France
| | - Beate Paulus
- Institut für Chemie und Biochemie, Freie Universität Berlin, D-14195, Berlin, Germany.
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23
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Schraivogel T, Cohen AJ, Alavi A, Kats D. Transcorrelated coupled cluster methods. J Chem Phys 2021; 155:191101. [PMID: 34800963 DOI: 10.1063/5.0072495] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transcorrelated coupled cluster and distinguishable cluster methods are presented. The Hamiltonian is similarity transformed with a Jastrow factor in the first quantization, which results in up to three-body integrals. The coupled cluster with singles and doubles equations on this transformed Hamiltonian are formulated and implemented. It is demonstrated that the resulting methods have a superior basis set convergence and accuracy to the corresponding conventional and explicitly correlated methods. Additionally, approximations for three-body integrals are suggested and tested.
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Affiliation(s)
- Thomas Schraivogel
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Aron J Cohen
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Ali Alavi
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Daniel Kats
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
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24
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Hill JG, Shaw RA. Correlation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential-based basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements. J Chem Phys 2021; 155:174113. [PMID: 34742216 DOI: 10.1063/5.0070638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
New correlation consistent basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements have been developed specifically for use in explicitly correlated F12 calculations. This includes orbital basis sets for valence only (cc-pVnZ-PP-F12, n = D, T, Q) and outer core-valence (cc-pCVnZ-PP-F12) correlation, along with both of these augmented with additional high angular momentum diffuse functions. Matching auxiliary basis sets required for density fitting and resolution-of-the-identity approaches to conventional and F12 integrals have also been optimized. All of the basis sets are to be used in conjunction with small-core relativistic pseudopotentials [Figgen et al., Chem. Phys. 311, 227 (2005)]. The accuracy of the basis sets is determined through benchmark calculation at the explicitly correlated coupled-cluster level of theory for various properties of atoms and diatomic molecules. The convergence of the properties with respect to the basis set is dramatically improved compared to conventional coupled-cluster calculations, with cc-pVTZ-PP-F12 results close to conventional estimates of the complete basis set limit. The patterns of convergence are also greatly improved compared to those observed from the use of conventional correlation consistent basis sets in F12 calculations.
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Affiliation(s)
- J Grant Hill
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Robert A Shaw
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
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25
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Fragmentation of Identical and Distinguishable Bosons’ Pairs and Natural Geminals of a Trapped Bosonic Mixture. ATOMS 2021. [DOI: 10.3390/atoms9040092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In a mixture of two kinds of identical bosons, there are two types of pairs: identical bosons’ pairs, of either species, and pairs of distinguishable bosons. In the present work, the fragmentation of pairs in a trapped mixture of Bose–Einstein condensates is investigated using a solvable model, the symmetric harmonic-interaction model for mixtures. The natural geminals for pairs made of identical or distinguishable bosons are explicitly contracted by diagonalizing the intra-species and inter-species reduced two-particle density matrices, respectively. Properties of pairs’ fragmentation in the mixture are discussed, the role of the mixture’s center-of-mass and relative center-of-mass coordinates is elucidated, and a generalization to higher-order reduced density matrices is made. As a complementary result, the exact Schmidt decomposition of the wave function of the bosonic mixture is constructed. The entanglement between the two species is governed by the coupling of their individual center-of-mass coordinates, and it does not vanish at the limit of an infinite number of particles where any finite-order intra-species and inter-species reduced density matrix per particle is 100% condensed. Implications are briefly discussed.
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26
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Laamiri K, Garcia GA, Nahon L, Ben Houria A, Feifel R, Hochlaf M. Threshold photoelectron spectroscopy of 9-methyladenine: theory and experiment. Phys Chem Chem Phys 2021; 24:3523-3531. [PMID: 34676858 DOI: 10.1039/d1cp03729c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We present a combined experimental and theoretical study of single-photon ionization of 9-methyladenine (9MA) in the gas phase. In addition to tautomerism, several rotamers due to the rotation of the methyl group may exist. Computations show, however, that solely one rotamer contributes because of low population in the molecular beam and/or unfavorable Franck-Condon factors upon ionization. Experimentally, we used VUV radiation available at the DESIRS beamline of the synchrotron radiation facility SOLEIL to record the threshold photoelectron spectrum of this molecule between 8 and 11 eV. This spectrum consists of a well-resolved band assigned mainly to vibronic levels of the D0 cationic state, plus a contribution from the D1 state, and two large bands corresponding to the D1, D2 and D3 electronically excited states. The adiabatic ionization energy of 9MA is measured at 8.097 ± 0.005 eV in close agreement with the computed value using the explicitly correlated coupled cluster approach including core valence, scalar relativistic and zero-point vibrational energy corrections. This work sheds light on the complex pattern of the lowest doublet electronic states of 9MA+. The comparison to canonical adenine reveals that methylation induces further electronic structure complication that may be important to understand the effects of ionizing radiation and the charge distribution in these biological entities at different time scales.
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Affiliation(s)
- K Laamiri
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs-sur-Marne, France. .,Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - G A Garcia
- Synchrotron SOLEIL, L'orme des Merisiers, Saint-Aubin - BP 48 - 91192 Gif-sur-Yvette Cedex, France
| | - L Nahon
- Synchrotron SOLEIL, L'orme des Merisiers, Saint-Aubin - BP 48 - 91192 Gif-sur-Yvette Cedex, France
| | - A Ben Houria
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - R Feifel
- University of Gothenburg, Department of Physics, 412 58 Gothenburg, Sweden
| | - M Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs-sur-Marne, France.
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27
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Quintas-Sánchez E, Dawes R, Denis-Alpizar O. Theoretical study of the HCS+–H2 van der Waals complex: potential energy surface, rovibrational bound states, and rotationally inelastic collisional cross sections. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1980234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Richard Dawes
- Department of Chemistry, Missouri University of Science and Technology, Rolla, USA
| | - Otoniel Denis-Alpizar
- Instituto de Ciencias Químicas Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Santiago, Chile
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28
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Olive LN, Dornshuld EV, Webster CE. The curious case of DMSO: A CCSD(T)/CBS(aQ56+d) benchmark and DFT study. J Chem Phys 2021; 155:114304. [PMID: 34551533 DOI: 10.1063/5.0057327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This work addresses the pathological behavior of the energetics of dimethyl sulfoxide and related sulfur-containing compounds by providing the computational benchmark energetics of R2E2 species, where R = H/CH3 and E = O/S, with bent and pyramidal geometries using state-of-the-art methodologies. These 22 geometries were fully characterized with coupled-cluster with single, double, and perturbative triple excitations [CCSD(T)], second-order Møller-Plesset perturbation theory (MP2), and 22 density functional theory (DFT) methods with 8, 12, and 12, respectively, correlation consistent basis sets of double-, triple-, or quadruple-ζ quality. The relative energetics were determined at the MP2 and CCSD(T) complete basis set (CBS) limits using 17 basis sets up to sextuple-ζ and include augmented, tight-d, and core-valence correlation consistent basis sets. The relative energies of oxygen-/sulfur-containing compounds exhibit exceptionally slow convergence to the CBS limit with canonical methods as well as significant basis set dependence. CCSD(T) with quadruple-ζ basis sets can give qualitatively incorrect relative energies. Explicitly correlated MP2-F12 and CCSD(T)-F12 methods dramatically accelerate the convergence of the relative energies to the CBS limit for these problematic compounds. The F12 methods with a triple-ζ quality basis set give relative energies that deviate no more than 0.41 kcal mol-1 from the benchmark CBS limit. The correlation consistent Composite Approach (ccCA), ccCA-TM (TM for transition metals), and G3B3 deviated by no more than 2 kcal mol-1 from the benchmark CBS limits. Relative energies for oxygen-/sulfur-containing systems fully characterized with DFT are quite unreliable even with triple-ζ quality basis sets, and 13 out of 45 combinations fortuitously give a relative energy that is within 1 kcal mol-1 on average from the benchmark CCSD(T) CBS limit for these systems.
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Affiliation(s)
- Laura N Olive
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762-9573, USA
| | - Eric Van Dornshuld
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762-9573, USA
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762-9573, USA
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29
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Chen J, Kato J, Harper JB, Shao Y, Ho J. On the Accuracy of QM/MM Models: A Systematic Study of Intramolecular Proton Transfer Reactions of Amino Acids in Water. J Phys Chem B 2021; 125:9304-9316. [PMID: 34355564 DOI: 10.1021/acs.jpcb.1c04876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work presents a systematic assessment of QM/QM' and QM/MM models with respect to direct QM calculations for the tautomerization (neutral to zwitterion) reactions of amino acids (glycine, alanine, valine, aspartate, and neutral and protonated histidine) solvated in a 160 water cluster. The effect of varying QM region size and choice of embedding potentials, including fixed-charge and polarizable molecular mechanics force fields (TIP3P and EFP) and various semiempirical QM methods (PM7, GFN2-xTB, DFTBA, DFTB3, HF-3c, and PBEh-3c), on the accuracy of the models was examined. A surprising finding was that molecular mechanics force fields outperformed many of the semiempirical methods. Generally, the errors in the QM/QM' and QM/MM models converge slowly with respect to the QM region size, requiring 50 or more waters to be included in the QM region before the error in the model falls below 1 kcal mol-1 of its pure QM result. Different QM region selection schemes were also compared, and it was found that selection based on Natural Population Analysis (NPA) atomic charges significantly reduced the error in the QM/QM' and QM/MM models particularly if a low-quality embedding potential was used. It is envisaged that these results will be useful for the development of future hybrid QM models.
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Affiliation(s)
- Junbo Chen
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Jin Kato
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Jason B Harper
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yihan Shao
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Junming Ho
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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30
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Esposito VJ, Trabelsi T, Francisco JS. Photochemistry of NH 2NO 2 and implications for chemistry in the atmosphere. J Chem Phys 2021; 154:194301. [PMID: 34240905 DOI: 10.1063/5.0050683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Recent studies have indicated that nitramide (NH2NO2) may be formed more plentifully in the atmosphere than previously thought, while also being a missing source of the greenhouse gas nitrous oxide (N2O) via catalyzed isomerization. To validate the importance of NH2NO2 in the Earth's atmosphere, the ground and first electronic excited states of NH2NO2 were characterized and its photochemistry was investigated using multireference and coupled cluster methods. NH2NO2 is non-planar and of singlet multiplicity in the ground state while exhibiting large out-of-plane rotation in the triplet first excited state. One-dimensional cuts of the adiabatic potential energy surface calculated using the MRCI+Q method show low-lying singlet electronic states with minima in their potential along the N-N and N-O bond coordinates. Due to vertical excitation energies in the 225-180 nm region, photochemical processes will not compete in the troposphere, causing N2O production to be the predicted major removal process of NH2NO2. In the upper atmosphere, photodissociation to form NH2NO + O (3P) is suggested to be a major photochemical removal pathway.
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Affiliation(s)
- Vincent J Esposito
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Tarek Trabelsi
- Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, USA
| | - Joseph S Francisco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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31
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Berndt T, Møller KH, Herrmann H, Kjaergaard HG. Trimethylamine Outruns Terpenes and Aromatics in Atmospheric Autoxidation. J Phys Chem A 2021; 125:4454-4466. [PMID: 33978422 DOI: 10.1021/acs.jpca.1c02465] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Autoxidation in the atmosphere has been realized in the last decade as an important process that forms highly oxidized products relevant for the formation of secondary organic aerosol and likely with detrimental human health effects. It is experimentally shown that the OH radical-initiated oxidation of trimethylamine, the most highly emitted amine in the atmosphere, proceeds via rapid autoxidation steps dominating its atmospheric oxidation process. All three methyl groups are functionalized within a timescale of 10 s following the reaction with OH radicals leading to highly oxidized products. The exceptionally large density of functional groups in the oxidized products is expected to define their chemical properties. A detailed reaction mechanism based on theoretical calculations is able to describe the experimental findings. The comparison with results of the reinvestigated OH radical- and ozone-initiated autoxidation of a series of terpenes and aromatics reveals the trimethylamine process as the most efficient one discovered up to now for atmospheric conditions.
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Affiliation(s)
- Torsten Berndt
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße 15, Leipzig 04318, Germany
| | - Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Hartmut Herrmann
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße 15, Leipzig 04318, Germany
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
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32
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Wang L, Wang L. The oxidation mechanism of gas-phase ozonolysis of limonene in the atmosphere. Phys Chem Chem Phys 2021; 23:9294-9303. [PMID: 33885076 DOI: 10.1039/d0cp05803c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Limonene with endo- and exo-double bonds is a significant monoterpene in the atmosphere and has high reactivity towards O3. We investigated the atmospheric oxidation mechanism of limonene ozonolysis using a high level quantum chemistry calculation coupled with RRKM-ME kinetic simulation. The additions of O3 can take place at both the endo- and exo-double bonds with a branching ratio of 0.87 : 0.13, forming four major highly energized CIs* (named Syn-2a*, Syn-2b*, Anti-2b* and Anti-2c*) with the relative higher fractions of 0.21 : 0.35 : 0.27 : 0.11. A yield of 4% for Limona-ketone was obtained as well. For the unimolecular isomerization pathways of limonene + O3 → POZs → CIs* → SOZ, VHP, or dioxirane, five, one, or none of the internal rotations are treated as hindered internal rotors for CIs*. We obtained percentages of 0.59 : 0.18 : 0.14 in total for separate isomerization routes in the formation of VHPs, dioxirane and SOZs from CIs* using the fourth-order Runge-Kutta method. Additionally, a yield of ∼5% was acquired for stabilized CIs compiling the fractions of different addition routes. About ∼10% of stabilized Anti-2b would isomerize to VHP and 90% would isomerize to SOZs. Isomerization to VHPs dominates the fate of stabilized Syn-2a, Syn-2b and Anti-2c. The overall yield of OH radicals was 0.61. Our study suggested a yield of 0.17 for stabilized SOZs and 0.18 for dioxirane, although both their fates are ambiguous.
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Affiliation(s)
- Lingyu Wang
- School of Chemistry & Chemical Engineering, South China University of Technology, 381 Wushan Rd., Guangzhou, 510640, China.
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33
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Mehta N, Fellowes T, White JM, Goerigk L. CHAL336 Benchmark Set: How Well Do Quantum-Chemical Methods Describe Chalcogen-Bonding Interactions? J Chem Theory Comput 2021; 17:2783-2806. [PMID: 33881869 DOI: 10.1021/acs.jctc.1c00006] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We present the CHAL336 benchmark set-the most comprehensive database for the assessment of chalcogen-bonding (CB) interactions. After careful selection of suitable systems and identification of three high-level reference methods, the set comprises 336 dimers each consisting of up to 49 atoms and covers both σ- and π-hole interactions across four categories: chalcogen-chalcogen, chalcogen-π, chalcogen-halogen, and chalcogen-nitrogen interactions. In a subsequent study of DFT methods, we re-emphasize the need for using proper London dispersion corrections when treating noncovalent interactions. We also point out that the deterioration of results and systematic overestimation of interaction energies for some dispersion-corrected DFT methods does not hint at problems with the chosen dispersion correction but is a consequence of large density-driven errors. We conclude this work by performing the most detailed DFT benchmark study for CB interactions to date. We assess 109 variations of dispersion-corrected and dispersion-uncorrected DFT methods and carry out a detailed analysis of 80 of them. Double-hybrid functionals are the most reliable approaches for CB interactions, and they should be used whenever computationally feasible. The best three double hybrids are SOS0-PBE0-2-D3(BJ), revDSD-PBEP86-D3(BJ), and B2NCPLYP-D3(BJ). The best hybrids in this study are ωB97M-V, PW6B95-D3(0), and PW6B95-D3(BJ). We do not recommend using the popular B3LYP functional nor the MP2 approach, which have both been frequently used to describe CB interactions in the past. We hope to inspire a change in computational protocols surrounding CB interactions that leads away from the commonly used, popular methods to the more robust and accurate ones recommended herein. We would also like to encourage method developers to use our set for the investigation and reduction of density-driven errors in new density functional approximations.
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Affiliation(s)
- Nisha Mehta
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Thomas Fellowes
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Jonathan M White
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Lars Goerigk
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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34
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Ma F, Guo X, Xia D, Xie HB, Wang Y, Elm J, Chen J, Niu J. Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4399-4409. [PMID: 33769798 DOI: 10.1021/acs.est.0c07925] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13-17% yield in the isoprene oxidation by •Cl, can contribute as much as 3.6-4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O2 to form peroxy radicals (RO2•). Under ≤100 ppt NO and ≤50 ppt HO2• conditions, the formed RO2• mainly undergo two times "successive cyclization and O2 addition" to finally form the product fragments 2-alkoxy-acetaldehyde (C2H3O2•) and 3-hydroperoxy-2-oxopropanal (C3H4O4). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C3H4O4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C5H7NO3, C5H7NO7, and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO2•.
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Affiliation(s)
- Fangfang Ma
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
- Department of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - Xirui Guo
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
| | - Deming Xia
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
| | - Hong-Bin Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
| | - Yonghong Wang
- Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
| | - Jonas Elm
- Department of Chemistry and iClimate, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), Dalian University of Technology, Dalian 116024, China
| | - Junfeng Niu
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, China
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35
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Kowalski K, Bair R, Bauman NP, Boschen JS, Bylaska EJ, Daily J, de Jong WA, Dunning T, Govind N, Harrison RJ, Keçeli M, Keipert K, Krishnamoorthy S, Kumar S, Mutlu E, Palmer B, Panyala A, Peng B, Richard RM, Straatsma TP, Sushko P, Valeev EF, Valiev M, van Dam HJJ, Waldrop JM, Williams-Young DB, Yang C, Zalewski M, Windus TL. From NWChem to NWChemEx: Evolving with the Computational Chemistry Landscape. Chem Rev 2021; 121:4962-4998. [PMID: 33788546 DOI: 10.1021/acs.chemrev.0c00998] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Since the advent of the first computers, chemists have been at the forefront of using computers to understand and solve complex chemical problems. As the hardware and software have evolved, so have the theoretical and computational chemistry methods and algorithms. Parallel computers clearly changed the common computing paradigm in the late 1970s and 80s, and the field has again seen a paradigm shift with the advent of graphical processing units. This review explores the challenges and some of the solutions in transforming software from the terascale to the petascale and now to the upcoming exascale computers. While discussing the field in general, NWChem and its redesign, NWChemEx, will be highlighted as one of the early codesign projects to take advantage of massively parallel computers and emerging software standards to enable large scientific challenges to be tackled.
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Affiliation(s)
- Karol Kowalski
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Raymond Bair
- Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Nicholas P Bauman
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | | | - Eric J Bylaska
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Jeff Daily
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Wibe A de Jong
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Thom Dunning
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Niranjan Govind
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Robert J Harrison
- Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, United States
| | - Murat Keçeli
- Argonne National Laboratory, Lemont, Illinois 60439, United States
| | | | | | - Suraj Kumar
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Erdal Mutlu
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Bruce Palmer
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Ajay Panyala
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Bo Peng
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | | | - T P Straatsma
- National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373, United States
| | - Peter Sushko
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Edward F Valeev
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Marat Valiev
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | | | | | | | - Chao Yang
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Marcin Zalewski
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Theresa L Windus
- Department of Chemistry, Iowa State University and Ames Laboratory, Ames, Iowa 50011, United States
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36
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Desrousseaux B, Quintas-Sánchez E, Dawes R, Marinakis S, Lique F. Collisional excitation of interstellar PN by H 2: New interaction potential and scattering calculations. J Chem Phys 2021; 154:034304. [PMID: 33499633 DOI: 10.1063/5.0039145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Rotational excitation of interstellar PN molecules induced by collisions with H2 is investigated. We present the first ab initio four-dimensional potential energy surface (PES) for the PN-H2 van der Waals system. The PES was obtained using an explicitly correlated coupled cluster approach with single, double, and perturbative triple excitations [CCSD(T)-F12b]. The method of interpolating moving least squares was used to construct an analytical PES from these data. The equilibrium structure of the complex was found to be linear, with H2 aligned at the N end of the PN molecule, at an intermolecular separation of 4.2 Å. The corresponding well-depth is 224.3 cm-1. The dissociation energies were found to be 40.19 cm-1 and 75.05 cm-1 for complexes of PN with ortho-H2 and para-H2, respectively. Integral cross sections for rotational excitation in PN-H2 collisions were calculated using the new PES and were found to be strongly dependent on the rotational level of the H2 molecule. These new collisional data will be crucial to improve the estimation of PN abundance in the interstellar medium from observational spectra.
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Affiliation(s)
- Benjamin Desrousseaux
- LOMC, UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 1123, 76063 Le Havre Cedex, France
| | - Ernesto Quintas-Sánchez
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, USA
| | - Richard Dawes
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, USA
| | - Sarantos Marinakis
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, Water Lane, London E15 4LZ, United Kingdom
| | - François Lique
- LOMC, UMR 6294, CNRS-Université du Havre, 25 rue Philippe Lebon, BP 1123, 76063 Le Havre Cedex, France
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37
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Chen J, Møller KH, Wennberg PO, Kjaergaard HG. Unimolecular Reactions Following Indoor and Outdoor Limonene Ozonolysis. J Phys Chem A 2021; 125:669-680. [DOI: 10.1021/acs.jpca.0c09882] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jing Chen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Kristian H. Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Paul O. Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Henrik G. Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
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38
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Ma Q, Werner HJ. Scalable Electron Correlation Methods. 8. Explicitly Correlated Open-Shell Coupled-Cluster with Pair Natural Orbitals PNO-RCCSD(T)-F12 and PNO-UCCSD(T)-F12. J Chem Theory Comput 2021; 17:902-926. [PMID: 33405921 DOI: 10.1021/acs.jctc.0c01129] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We present explicitly correlated open-shell pair natural orbital local coupled-cluster methods, PNO-RCCSD(T)-F12 and PNO-UCCSD(T)-F12. The methods are extensions of our previously reported PNO-R/UCCSD methods (J. Chem. Theory Comput., 2020, 16, 3135-3151, https://pubs.acs.org/doi/10.1021/acs.jctc.0c00192) with additions of explicit correlation and perturbative triples corrections. The explicit correlation treatment follows the spin-orbital CCSD-F12b theory using Ansatz 3*A, which is found to yield comparable or better basis set convergence than the more rigorous Ansatz 3C in computed ionization potentials and reaction energies using double- to quaduple-ζ basis sets. The perturbative triples correction is adapted from the spin-orbital (T) theory to use triples natural orbitals (TNOs). To address the coupling due to off-diagonal Fock matrix elements, the local triples amplitudes are iteratively solved using small domains of TNOs, and a semicanonical (T0) domain correction with larger domains is applied to reduce the domain errors. The performance of the methods is demonstrated through benchmark calculations on ionization potentials, radical stabilization energies, reaction energies of fragmentations and rearrangements in radical cations, and spin-state energy differences of iron complexes. For a few test sets where canonical calculations are feasible, PNO-RCCSD(T)-F12 results agree with the canonical ones to within 0.4 kcal mol-1, and this maximum error is reduced to below 0.2 kcal mol-1 when large local domains are used. For larger systems, results using different thresholds for the local approximations are compared to demonstrate that 1 kcal mol-1 level of accuracy can be achieved using our default settings. For a couple of difficult cases, it is demonstrated that the errors from individual approximations are only a fraction of 1 kcal mol-1, and the overall accuracy of the method does not rely on error compensations. In contrast to canonical calculations, the use of spin-orbitals does not lead to a significant increase of computational time and memory usage in the most expensive steps of PNO-R/UCCSD(T)-F12 calculations. The only exception is the iterative solution of the (T) amplitudes, which can be avoided without significant errors by using a perturbative treatment of the off-diagonal coupling, known as (T1) approximation. For most systems, even the semicanonical approximation (T0) leads only to small errors in relative energies. Our program is well parallelized and capable of computing accurate correlation energies for molecules with 100-200 atoms using augmented triple-ζ basis sets in less than a day of elapsed time on a small computer cluster.
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Affiliation(s)
- Qianli Ma
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - Hans-Joachim Werner
- Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
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Mehta N, Goerigk L. Assessing the Applicability of the Geometric Counterpoise Correction in B2PLYP/Double-ζ Calculations for Thermochemistry, Kinetics, and Noncovalent Interactions. Aust J Chem 2021. [DOI: 10.1071/ch21133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We present a proof-of-concept study of the suitability of Kruse and Grimme’s geometric counterpoise correction (gCP) for basis set superposition errors (BSSEs) in double-hybrid density functional calculations with a double-ζ basis set. The gCP approach only requires geometrical information as an input and no orbital/density information is needed. Therefore, this correction is practically free of any additional cost. gCP is trained against the Boys and Bernardi counterpoise correction across a set of 528 noncovalently bound dimers. We investigate the suitability of the approach for the B2PLYP/def2-SVP level of theory, and reveal error compensation effects—missing London dispersion and the BSSE—associated with B2PLYP/def2-SVP calculations, and present B2PLYP-gCP-D3(BJ)/def2-SVP with the reparametrised DFT-D3(BJ) and gCP corrections as a more balanced alternative. Benchmarking results on the S66x8 benchmark set for noncovalent interactions and the GMTKN55 database for main-group thermochemistry, kinetics, and noncovalent interactions show a statistical improvement of the B2PLYP-gCP-D3(BJ) scheme over plain B2PLYP and B2PLYP-D3(BJ). B2PLYP-D3(BJ) shows significant overestimation of interaction energies, barrier heights with larger deviations from the reference values, and wrong relative stabilities in conformers, all of which can be associated with BSSE. We find that the gCP-corrected method represents a significant improvement over B2PLYP-D3(BJ), particularly for intramolecular noncovalent interactions. These findings encourage future developments of efficient double-hybrid DFT strategies that can be applied when double-hybrid calculations with large basis sets are not feasible due to system size.
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40
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Bader F, Tremblay JC, Paulus B. A pair potential modeling study of F3− in neon matrices. Phys Chem Chem Phys 2021; 23:886-899. [DOI: 10.1039/d0cp05031h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First-principles investigations of the trifluoride anion in a neon environment reveal a small blue-shift of the fundamental vibrational excitations.
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Affiliation(s)
- Frederik Bader
- Institut für Chemie und Biochemie
- Freie Universität Berlin
- D-14195, Berlin
- Germany
| | | | - Beate Paulus
- Institut für Chemie und Biochemie
- Freie Universität Berlin
- D-14195, Berlin
- Germany
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41
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Mosquera-Lois I, Ferro-Costas D, Fernández-Ramos A. Chemical reactivity from the vibrational ground-state level. The role of the tunneling path in the tautomerization of urea and derivatives. Phys Chem Chem Phys 2020; 22:24951-24963. [PMID: 33140774 DOI: 10.1039/d0cp04857g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent developments of low-temperature techniques are providing valuable knowledge about chemical processes that manifest in the quantum regimen. The tunneling effect from the vibrational ground-state is the main mechanism of these reactions, which usually involves the motion or transfer of hydrogen atoms. Theoretical methods can enrich the information supplied by these experimental methods through an insightful analysis of the tunneling process. In this context, canonical variational transition state theory with multidimensional tunneling corrections (CVT/MT) can handle this type of reaction, and it has been applied to several systems within the small-curvature approximation for tunneling (SCT). This method is of proven reliability for polyatomic reactions occurring at room temperature and above, but no tests have been performed to check its performance when only the lowest energy level is populated. In this work, we compare SCT against the least-action tunneling (LAT) method to study the tautomerization and cis-trans interconversion reactions in the enol forms of urea, thiourea, and selenourea. To the best of our knowledge, this is the first time that the LAT method is applied to a polyatomic reaction occurring in the deep-tunneling region. The theoretical results indicate that the reaction mechanisms are controlled by tunneling. The SCT and LAT tautomerization reaction times are in good agreement with the experimental values; however, LAT seems superior to SCT for reactions (tautomerizations) that involve moderate reaction path curvature, whereas the opposite is true for reactions with small curvature (interconversions). These results led us to introduce and recommend the microcanonically optimized tunneling path that selects the tunneling probability as the maximum between the SCT and LAT tunneling probabilities.
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Affiliation(s)
- Irea Mosquera-Lois
- Center for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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42
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Xu L, Møller KH, Crounse JD, Kjaergaard HG, Wennberg PO. New Insights into the Radical Chemistry and Product Distribution in the OH-Initiated Oxidation of Benzene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13467-13477. [PMID: 33084314 DOI: 10.1021/acs.est.0c04780] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Emissions of aromatic compounds cause air pollution and detrimental health effects. Here, we explore the reaction kinetics and products of key radicals in benzene photo-oxidation. After initial OH addition and reaction with O2, the effective production rates of phenol and bicyclic peroxy radical (BCP-peroxy) are experimentally constrained at 295 K to be 420 ± 80 and 370 ± 70 s-1, respectively. These rates lead to approximately 53% yield for phenol and 47% yield for BCP-peroxy under atmospheric conditions. The reaction of BCP-peroxy with NO produces bicyclic hydroxy nitrate with a branching ratio <0.2%, indicating efficient NOx recycling. Similarly, the reaction of BCP-peroxy with HO2 largely recycles HOx, producing the corresponding bicyclic alkoxy radical (BCP-oxy). Because of the presence of C-C double bonds and multiple functional groups, the chemistry of BCP-oxy and other alkoxy radicals in the system is diverse. Experimental results suggest the aldehydic H-shift and ring-closure to produce an epoxide functionality could be competitive with classic decomposition of alkoxy radicals. These reactions are potential sources of highly oxygenated molecules. Finally, despite the large number of compounds observed in our study, we are unable to account for ∼20% of the carbon flow.
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Affiliation(s)
- Lu Xu
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States
| | - Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken5, DK-2100 Copenhagen Ø, Denmark
| | - John D Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken5, DK-2100 Copenhagen Ø, Denmark
| | - Paul O Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, United States
- Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, United States
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43
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Quintas-Sánchez E, Dawes R, Wang XG, Carrington T. Computational study of the rovibrational spectrum of CO 2-N 2. Phys Chem Chem Phys 2020; 22:22674-22683. [PMID: 33016299 DOI: 10.1039/d0cp04186f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The CO2-N2 complex is formed from two key components of Earth's atmosphere, and as such, has received some attention from both experimental and theoretical studies. On the theory side, a potential energy surface (PES) based on high level ab initio data was reported [Nasri et al., J. Chem. Phys., 2015, 142, 174301] and then used in more recently reported rovibrational calculations [Lara-Moreno et al., Phys. Chem. Chem. Phys., 2019, 21, 3550]. Accuracy of about 1 percent was achieved for calculated rotational transitions of the ground vibrational state of the complex, compared with previously reported microwave spectra. However, a very recent measurement of the geared bending mode frequency [Barclay et al., J. Chem. Phys., 2020, 153, 014303] recorded a value of 21.4 cm-1, which is wildly different from the corresponding calculated value of 45.9 cm-1. To provide some insight into this discrepancy, we have constructed a new more accurate PES, and used it to perform highly converged variational rovibrational calculations. Our new results yield a value of 21.1 cm-1 for that bending frequency, in close agreement with the experiment. We also obtain significantly improved predicted rotational transitions. Finally, we note that a very shallow well, previously reported as a distinct second isomer, is not found on our new PES, but rather a transition structure is seen in that location.
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Zuraski K, Hui AO, Grieman FJ, Darby E, Møller KH, Winiberg FAF, Percival CJ, Smarte MD, Okumura M, Kjaergaard HG, Sander SP. Acetonyl Peroxy and Hydro Peroxy Self- and Cross-Reactions: Kinetics, Mechanism, and Chaperone Enhancement from the Perspective of the Hydroxyl Radical Product. J Phys Chem A 2020; 124:8128-8143. [PMID: 32852951 DOI: 10.1021/acs.jpca.0c06220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pulsed laser photolysis coupled with infrared (IR) wavelength modulation spectroscopy and ultraviolet (UV) absorption spectroscopy was used to study the kinetics and branching fractions for the acetonyl peroxy (CH3C(O)CH2O2) self-reaction and its reaction with hydro peroxy (HO2) at a temperature of 298 K and pressure of 100 Torr. Near-IR and mid-IR lasers simultaneously monitored HO2 and hydroxyl, OH, respectively, while UV absorption measurements monitored the CH3C(O)CH2O2 concentrations. The overall rate constant for the reaction between CH3C(O)CH2O2 and HO2 was found to be (5.5 ± 0.5) × 10-12 cm3 molecule-1 s-1, and the branching fraction for OH yield from this reaction was directly measured as 0.30 ± 0.04. The CH3C(O)CH2O2 self-reaction rate constant was measured to be (4.8 ± 0.8) × 10-12 cm3 molecule-1 s-1, and the branching fraction for alkoxy formation was inferred from secondary chemistry as 0.33 ± 0.13. An increase in the rate of the HO2 self-reaction was also observed as a function of acetone (CH3C(O)CH3) concentration which is interpreted as a chaperone effect, resulting from hydrogen-bond complexation between HO2 and CH3C(O)CH3. The chaperone enhancement coefficient for CH3C(O)CH3 was determined to be kA″ = (4.0 ± 0.2) × 10-29 cm6 molecule-2 s-1, and the equilibrium constant for HO2·CH3C(O)CH3 complex formation was found to be Kc(R14) = (2.0 ± 0.89) × 10-18 cm3 molecule-1; from these values, the rate constant for the HO2 + HO2·CH3C(O)CH3 reaction was estimated to be (2 ± 1) × 10-11 cm3 molecule-1 s-1. Results from UV absorption cross-section measurements of CH3C(O)CH2O2 and prompt OH radical yields arising from possible oxidation of the CH3C(O)CH3-derived alkyl radical are also discussed. Using theoretical methods, no likely pathways for the observed prompt OH radical formation have been found and the prompt OH radical yields thus remain unexplained.
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Affiliation(s)
- Kristen Zuraski
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Aileen O Hui
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Fred J Grieman
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,Seaver Chemistry Laboratory, Pomona College, Claremont, California 91711, United States
| | - Emily Darby
- Seaver Chemistry Laboratory, Pomona College, Claremont, California 91711, United States
| | - Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Frank A F Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Carl J Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Matthew D Smarte
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Mitchio Okumura
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Stanley P Sander
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
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45
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Hasan G, Salo VT, Valiev RR, Kubečka J, Kurtén T. Comparing Reaction Routes for 3(RO···OR') Intermediates Formed in Peroxy Radical Self- and Cross-Reactions. J Phys Chem A 2020; 124:8305-8320. [PMID: 32902986 DOI: 10.1021/acs.jpca.0c05960] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Organic peroxy radicals (RO2) are key intermediates in the chemistry of the atmosphere. One of the main sink reactions of RO2 is the recombination reaction RO2 + R'O2, which has three main channels (all with O2 as a coproduct): (1) R-H═O + R'OH, (2) RO + R'O, and (3) ROOR'. The RO + R'O "alkoxy" channel promotes radical and oxidant recycling, while the ROOR' "dimer" channel leads to low-volatility products relevant to aerosol processes. The ROOR' channel has only recently been discovered to play a role in the gas phase. Recent computational studies indicate that all of these channels first go through an intermediate complex 1(RO···3O2···OR'). Here, 3O2 is very weakly bound and will likely evaporate from the system, giving a triplet cluster of two alkoxy radicals: 3(RO···OR'). In this study, we systematically investigate the three reaction channels for an atmospherically representative set of RO + R'O radicals formed in the corresponding RO2 + R'O2 reaction. First, we systematically sample the possible conformations of the RO···OR' clusters on the triplet potential energy surface. Next, we compute energetic parameters and attempt to estimate reaction rate coefficients for the three channels: evaporation/dissociation to RO + R'O, a hydrogen shift leading to the formation of R'-H═O + ROH, and "spin-flip" (intersystem crossing) leading to, or at least allowing, the formation of ROOR' dimers. While large uncertainties in the computed energetics prevent a quantitative comparison of reaction rates, all three channels were found to be very fast (with typical rates greater than 106 s-1). This qualitatively demonstrates that the computationally proposed novel RO2 + R'O2 reaction mechanism is compatible with experimental data showing non-negligible branching ratios for all three channels, at least for sufficiently complex RO2.
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Affiliation(s)
- Galib Hasan
- Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.,Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Vili-Taneli Salo
- Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.,Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Rashid R Valiev
- Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.,Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Jakub Kubečka
- Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Theo Kurtén
- Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.,Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
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Møller KH, Berndt T, Kjaergaard HG. Atmospheric Autoxidation of Amines. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11087-11099. [PMID: 32786344 DOI: 10.1021/acs.est.0c03937] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Autoxidation has been acknowledged as a major oxidation pathway in a broad range of atmospherically important compounds including isoprene, monoterpenes, and very recently, dimethyl sulfide. Here, we present a high-level theoretical multiconformer transition-state theory study of the atmospheric autoxidation in amines exemplified by the atmospherically important trimethylamine (TMA) and dimethylamine and generalized by the study of the larger diethylamine. Overall, we find that the initial hydrogen shift reactions have rate coefficients greater than 0.1 s-1 and autoxidation is thus an important atmospheric pathway for amines. This autoxidation efficiently leads to the formation of hydroperoxy amides, a new type of atmospheric nitrogen-containing compounds, and for TMA, we experimentally confirm this. The conversion of amines to hydroperoxy amides may have important implications for nucleation and growth of atmospheric secondary organic aerosols and atmospheric OH recycling.
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Affiliation(s)
- Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Torsten Berndt
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße 15, 04318 Leipzig, Germany
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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47
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Paiva P, Ramos MJ, Fernandes PA. Assessing the validity of DLPNO-CCSD(T) in the calculation of activation and reaction energies of ubiquitous enzymatic reactions. J Comput Chem 2020; 41:2459-2468. [PMID: 32882060 DOI: 10.1002/jcc.26401] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 12/31/2022]
Abstract
The domain-based local pair natural orbital coupled-cluster with single, double, and perturbative triples excitation (DLPNO-CCSD(T)) method was employed to portray the activation and reaction energies of four ubiquitous enzymatic reactions, and its performance was confronted to CCSD(T)/complete basis set (CBS) to assess its accuracy and robustness in this specific field. The DLPNO-CCSD(T) results were also confronted to those of a set of density functionals (DFs) to understand the benefit of implementing this technique in enzymatic quantum mechanics/molecular mechanics (QM/MM) calculations as a second QM component, which is often treated with DF theory (DFT). On average, the DLPNO-CCSD(T)/aug-cc-pVTZ results were 0.51 kcal·mol-1 apart from the canonic CCSD(T)/CBS, without noticeable biases toward any of the reactions under study. All DFs fell short to the DLPNO-CCSD(T), both in terms of accuracy and robustness, which suggests that this method is advantageous to characterize enzymatic reactions and that its use in QM/MM calculations, either alone or in conjugation with DFT, in a two-region QM layer (DLPNO-CCSD(T):DFT), should enhance the quality and faithfulness of the results.
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Affiliation(s)
- Pedro Paiva
- LAQV@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Maria J Ramos
- LAQV@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Pedro A Fernandes
- LAQV@REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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48
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Lupi J, Puzzarini C, Cavallotti C, Barone V. State-of-the-Art Quantum Chemistry Meets Variable Reaction Coordinate Transition State Theory to Solve the Puzzling Case of the H 2S + Cl System. J Chem Theory Comput 2020; 16:5090-5104. [PMID: 32603107 PMCID: PMC8009477 DOI: 10.1021/acs.jctc.0c00354] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The atmospheric reaction of H2S with Cl has been reinvestigated to check if, as previously suggested, only explicit dynamical computations can lead to an accurate evaluation of the reaction rate because of strong recrossing effects and the breakdown of the variational extension of transition state theory. For this reason, the corresponding potential energy surface has been thoroughly investigated, thus leading to an accurate characterization of all stationary points, whose energetics has been computed at the state of the art. To this end, coupled-cluster theory including up to quadruple excitations has been employed, together with the extrapolation to the complete basis set limit and also incorporating core-valence correlation, spin-orbit, and scalar relativistic effects as well as diagonal Born-Oppenheimer corrections. This highly accurate composite scheme has also been paralleled by less expensive yet promising computational approaches. Moving to kinetics, variational transition state theory and its variable reaction coordinate extension for barrierless steps have been exploited, thus obtaining a reaction rate constant (8.16 × 10-11 cm3 molecule-1 s-1 at 300 K and 1 atm) in remarkable agreement with the experimental counterpart. Therefore, contrary to previous claims, there is no need to invoke any failure of the transition state theory, provided that sufficiently accurate quantum-chemical computations are performed. The investigation of the puzzling case of the H2S + Cl system allowed us to present a robust approach for disclosing the thermochemistry and kinetics of reactions of atmospheric and astrophysical interest.
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Affiliation(s)
- Jacopo Lupi
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
| | - Cristina Puzzarini
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Via F. Selmi 2, I-40126 Bologna, Italy
| | - Carlo Cavallotti
- Department of Chemistry, Materials, and Chemical Engineering "G. Natta", Politecnico di Milano, I-20131 Milano, Italy
| | - Vincenzo Barone
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy
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49
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Kilaj A, Gao H, Tahchieva D, Ramakrishnan R, Bachmann D, Gillingham D, von Lilienfeld OA, Küpper J, Willitsch S. Quantum-chemistry-aided identification, synthesis and experimental validation of model systems for conformationally controlled reaction studies: separation of the conformers of 2,3-dibromobuta-1,3-diene in the gas phase. Phys Chem Chem Phys 2020; 22:13431-13439. [PMID: 32515452 DOI: 10.1039/d0cp01396j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Diels-Alder cycloaddition, in which a diene reacts with a dienophile to form a cyclic compound, counts among the most important tools in organic synthesis. Achieving a precise understanding of its mechanistic details on the quantum level requires new experimental and theoretical methods. Here, we present an experimental approach that separates different diene conformers in a molecular beam as a prerequisite for the investigation of their individual cycloaddition reaction kinetics and dynamics under single-collision conditions in the gas phase. A low- and high-level quantum-chemistry-based screening of more than one hundred dienes identified 2,3-dibromobutadiene (DBB) as an optimal candidate for efficient separation of its gauche and s-trans conformers by electrostatic deflection. A preparation method for DBB was developed which enabled the generation of dense molecular beams of this compound. The theoretical predictions of the molecular properties of DBB were validated by the successful separation of the conformers in the molecular beam. A marked difference in photofragment ion yields of the two conformers upon femtosecond-laser pulse ionization was observed, pointing at a pronounced conformer-specific fragmentation dynamics of ionized DBB. Our work sets the stage for a rigorous examination of mechanistic models of cycloaddition reactions under controlled conditions in the gas phase.
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Affiliation(s)
- Ardita Kilaj
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland.
| | - Hong Gao
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland. and Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Diana Tahchieva
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland.
| | - Raghunathan Ramakrishnan
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland. and Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad 500107, India
| | - Daniel Bachmann
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland.
| | - Dennis Gillingham
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland.
| | - O Anatole von Lilienfeld
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland. and National Center for Computational Design and Discovery of Novel Materials (MARVEL), University of Basel, 4056 Basel, Switzerland
| | - Jochen Küpper
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany and Department of Physics, Universität Hamburg, 22761 Hamburg, Germany and Department of Chemistry, Universität Hamburg, 20146 Hamburg, Germany and Center for Ultrafast Imaging, Universität Hamburg, 22761 Hamburg, Germany
| | - Stefan Willitsch
- Department of Chemistry, University of Basel, 4056 Basel, Switzerland.
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Perkins MA, Barlow KR, Dreux KM, Tschumper GS. Anchoring the hydrogen sulfide dimer potential energy surface to juxtapose (H2S)2 with (H2O)2. J Chem Phys 2020; 152:214306. [DOI: 10.1063/5.0008929] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Morgan A. Perkins
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, USA
| | - Kayleigh R. Barlow
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, USA
| | - Katelyn M. Dreux
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, USA
| | - Gregory S. Tschumper
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, USA
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