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Zhang C, Peterson KA, Dyall KG, Cheng L. A new computational framework for spinor-based relativistic exact two-component calculations using contracted basis functions. J Chem Phys 2024; 161:054105. [PMID: 39087536 DOI: 10.1063/5.0217762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/14/2024] [Indexed: 08/02/2024] Open
Abstract
A new computational framework for spinor-based relativistic exact two-component (X2C) calculations is developed using contracted basis sets with a spin-orbit contraction scheme. Generally contracted, j-adapted basis sets of p-block elements using primitive functions in the correlation-consistent basis sets are constructed for the X2C Hamiltonian with atomic mean-field spin-orbit integrals (the X2CAMF scheme). The contraction coefficients are taken from atomic X2CAMF Hartree-Fock spinors, thereby following the simple concept of a linear combination of atomic orbitals. Benchmark calculations of spin-orbit splittings, equilibrium bond lengths, and harmonic vibrational frequencies demonstrate the accuracy and efficacy of the j-adapted spin-orbit contraction scheme.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Kirk A Peterson
- Department of Chemistry, Washington State University, Pullman, Washington 99164, USA
| | | | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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2
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Gregory KP, Wanless EJ, Webber GB, Craig VSJ, Page AJ. A first-principles alternative to empirical solvent parameters. Phys Chem Chem Phys 2024; 26:20750-20759. [PMID: 38988220 DOI: 10.1039/d4cp01975j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
The use of solvents is ubiquitous in chemistry. Empirical parameters, such as the Kamlet-Taft parameters and Gutmann donor/acceptor numbers, have long been used to predict and quantify the effects solvents have on chemical phenomena. Collectively however, such parameters are unsatisfactory, since each describes ultimately the same non-covalent solute-solvent and solute-solute interactions in completely disparate ways. Here we hypothesise that empirical solvent parameters are essentially proxy measures of the electrostatic terms that dominate solvent-solute interactions. On the basis of this hypothesis, we develop a new fundamental descriptor of these interactions, , and show that it is a self-consistent, probe-free, first principles alternative to established empirical solvent parameters.
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Affiliation(s)
- Kasimir P Gregory
- Discipline of Chemistry, College of Engineering, Science & Environment, University of Newcastle, Callaghan 2308, Australia.
- Research School of Materials Physics, Research School of Physics, Australian National University, ACT 0200, Australia
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Erica J Wanless
- Discipline of Chemistry, College of Engineering, Science & Environment, University of Newcastle, Callaghan 2308, Australia.
| | - Grant B Webber
- Discipline of Chemical Engineering, College of Engineering, Science & Environment, University of Newcastle, Callaghan 2308, Australia
| | - Vincent S J Craig
- Research School of Materials Physics, Research School of Physics, Australian National University, ACT 0200, Australia
| | - Alister J Page
- Discipline of Chemistry, College of Engineering, Science & Environment, University of Newcastle, Callaghan 2308, Australia.
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3
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Wu Z, Walser S, Podlesnic V, Isaza-Monsalve M, Mattivi E, Mu G, Nardi R, Gniewek P, Tomza M, Furey BJ, Schindler P. Photodissociation spectra of single trapped CaOH+ molecular ions. J Chem Phys 2024; 161:044304. [PMID: 39037137 DOI: 10.1063/5.0217685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 07/08/2024] [Indexed: 07/23/2024] Open
Abstract
Molecular ions that are generated by chemical reactions with trapped atomic ions can serve as an accessible testbed for developing molecular quantum technologies. On the other hand, they are also a hindrance to scaling up quantum computers based on atomic ions, as unavoidable reactions with background gases destroy the information carriers. Here, we investigate the single- and two-photon dissociation processes of single CaOH+ molecular ions co-trapped in Ca+ ion crystals using a femtosecond laser system. We report the photodissociation cross section spectra of CaOH+ for single-photon processes at λ = 245-275 nm and for two-photon processes at λ = 500-540 nm. Measurements are interpreted with quantum-chemical calculations, which predict the photodissociation threshold for CaOH+ → Ca+ + OH at 265 nm. This result can serve as a basis for dissociation-based spectroscopy for studying the internal structure of CaOH+. The result also gives a prescription for recycling Ca+ ions in large-scale trapped Ca+ quantum experiments from undesired CaOH+ ions formed in the presence of background water vapor.
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Affiliation(s)
- Zhenlin Wu
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Stefan Walser
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Verena Podlesnic
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Mariano Isaza-Monsalve
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Elyas Mattivi
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Guanqun Mu
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - René Nardi
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Piotr Gniewek
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Michał Tomza
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Brandon J Furey
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
| | - Philipp Schindler
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25/4, 6020 Innsbruck, Austria
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4
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Wen X, Boyn JN, Martirez JMP, Zhao Q, Carter EA. Strategies to Obtain Reliable Energy Landscapes from Embedded Multireference Correlated Wavefunction Methods for Surface Reactions. J Chem Theory Comput 2024; 20:6037-6048. [PMID: 39004994 DOI: 10.1021/acs.jctc.4c00558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Embedded correlated wavefunction (ECW) theory is a powerful tool for studying ground- and excited-state reaction mechanisms and associated energetics in heterogeneous catalysis. Several factors are important to obtaining reliable ECW energies, critically the construction of consistent active spaces (ASs) along reaction pathways when using a multireference correlated wavefunction (CW) method that relies on a subset of orbital spaces in the configuration interaction expansion to account for static electron correlation, e.g., complete AS self-consistent field theory, in addition to the adequate partitioning of the system into a cluster and environment, as well as the choice of a suitable basis set and number of states included in excited-state simulations. Here, we conducted a series of systematic studies to develop best-practice guidelines for ground- and excited-state ECW theory simulations, utilizing the decomposition of NH3 on Pd(111) as an example. We determine that ECW theory results are relatively insensitive to cluster size, the aug-cc-pVDZ basis set provides an adequate compromise between computational complexity and accuracy, and that a fixed-clean-surface approximation holds well for the derivation of the embedding potential. Additionally, we demonstrate that a merging approach, which involves generating ASs from the molecular fragments at each configuration, is preferable to a creeping approach, which utilizes ASs from adjacent structures as an initial guess, for the generation of consistent potential energy curves involving open-d-shell metal surfaces, and, finally, we show that it is essential to include bands of excited states in their entirety when simulating excited-state reaction pathways.
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Affiliation(s)
- Xuelan Wen
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, United States
| | - Jan-Niklas Boyn
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, United States
| | - John Mark P Martirez
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540-6655, United States
| | - Qing Zhao
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, United States
| | - Emily A Carter
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, United States
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540-6655, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544-5263, United States
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5
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Loudermilk A, Dixon DA. Prediction of the p Ka's of Hydrated Metal Carbonates and Bicarbonates for Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn Dications. J Phys Chem A 2024; 128:5331-5343. [PMID: 38950028 DOI: 10.1021/acs.jpca.4c02879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
The gas- and aqueous-phase acidities of hydrated metal dication carbonates, bicarbonates, and hydroxide complexes M(CO3)(H2O)n for n = 1 to 3, M(HCO3)2, M(HCO3)2(H2O)2, M(HCO3)(OH), and M(HCO3)(H2O)2(OH) for M = Mg, Ca, Mn, Fe, Co, Ni, Cu, and Zn were calculated at the CCSD(T)/aug-cc-pwCVDZ/cc-pwCVDZ level in the gas phase and at the B3LYP/aug-cc-pVTZ/cc-pVTZ(-PP) level with the COSMO self-consistent reaction field (SCRF) method in the aqueous phase. The composite correlated molecular orbital theory G3(MP2) and G3(MP2)B3 methods were used to predict the pKa's of the Mg structures and cis-cis carbonic acid to provide additional benchmarks. Using values scaled to experiment for H2CO3, the pKa's of bicarbonate ligands in group 2 and transition-metal complexes were compared to carbonic acid to gauge the effect of the metal complex on the bicarbonate. The group 2 metal complexes M(HCO3)2 and M(HCO3)(OH) decreased the acidity of the bicarbonate ligands, whereas their dihydrates were even less acidic. The transition-metal di-bicarbonate and bicarbonate hydroxide complexes generally made the bicarbonate more acidic especially when reduction of the metal occurs consistent with electron donation from the ligands; this is accompanied by spin transfer which typically increases in the order Mn < Fe < Co < Ni < Cu. The transition-metal dihydrates were less acidic than carbonic acid. Using values scaled to experiment for hydrated metal dications, the pKa's of water coordinated to group 2 and transition-metal complexes were generally more acidic than the hydrated metal dications, with the exception of Ca bicarbonate dihydrate, Co carbonate, Ni di-bicarbonate dihydrate, and Cu bicarbonate hydroxide di-bicarbonate.
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Affiliation(s)
- Amanda Loudermilk
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
| | - David A Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States
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6
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Ariyarathna IR. Ab initio exploration of low-lying electronic states of linear and bent MNX + (M = Ca, Sr, Ba, Ra; X = O, S, Se, Te, Po) and their origins. J Comput Chem 2024. [PMID: 38981130 DOI: 10.1002/jcc.27456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/10/2024] [Accepted: 06/12/2024] [Indexed: 07/11/2024]
Abstract
High-level multireference and coupled cluster quantum calculations were employed to analyze low-lying electronic states of linear-MNX+ and side-bonded-M[NX]+ (M = Ca, Sr, Ba, Ra; X = O, S, Se, Te, Po) species. Their full potential energy curves (PECs), dissociation energies (Des), geometric parameters, excitation energies (Tes), and harmonic vibrational frequencies (ωes) are reported. The first three chemically bound electronic states of MNX+ and M[NX]+ are 3Σ-, 1Δ, 1Σ+ and 3A″, 1A', 1A″, respectively. The 3Σ-, 1Δ, 1Σ+ of MNX+ originate from the M+(2D) + NX(2Π) fragments, whereas the 3A″, 1A', 1A″ states of M[NX]+ dissociate to M+(2S) + NX(2Π) as a result of avoided crossings. The MNX+ and M[NX]+ are real minima on the potential energy surface and their interconversions are possible. The M2+NX-/M2+[NX]- ionic structure is an accurate representation for their low-lying electronic states. The Des of MNX+ species were found to depend on the dipole moment (μ) of the corresponding NX ligands and a linear relationship between these two parameters was observed.
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Affiliation(s)
- Isuru R Ariyarathna
- Physics and Chemistry of Materials (T-1), Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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7
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Ariyarathna IR. Electronic structure analysis and DFT benchmarking of Rydberg-type alkali-metal-crown ether, -cryptand, and -adamanzane complexes. Phys Chem Chem Phys 2024; 26:16989-16997. [PMID: 38666396 DOI: 10.1039/d4cp00723a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Density functional theory (DFT) and electron propagator theory (EPT) calculations were performed to study ground and excited electronic structures of alkali-metal (M) coordinated 9-crown-3, 24-crown-8, [2.1.1]cryptand, o-Me2-1.1.1, and 36Adamanzane complexes. Each complex bears an expanded electron in the periphery and occupies diffuse 1p-, 1d-, 1f-type molecular orbitals (or superatomic 1P, 1D, 1F orbitals) in excited electronic states. The calculated superatomic shell model of the M(9-crown-3)2 is 1S, 1P, 1D, 1F, 2S, 2P, 2D, 1G and it is held by all other complexes up to the studied 1F level. Due to the highly diffuse nature of the electron, the ionization energies of these complexes are significantly lower (1.6-2.0 eV) and hence these complexes belong to the superalkali category. The ab initio EPT ionization energy and the excitation energies of the Li(9-crown-3)2 were used to evaluate DFT errors associated with a series of exchange correlation functionals that span multiple rungs of Jacob's ladder (i.e., GGA, meta-GGA, global GGA hybrid, meta-GGA hybrid, range-separated hybrid, double-hybrid). Among these, the best performing functional is the range-separated hybrid CAM-B3LYP and the errors are within 6% of high-level ab initio EPT results. The accuracy of CAM-B3LYP is indeed transferable to similar complexes and hence the findings are expected to accelerate the progression of studies of Rydberg-type systems.
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Affiliation(s)
- Isuru R Ariyarathna
- Physics and Chemistry of Materials (T-1), Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
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8
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Park E, Park J, Kim I, Kim J, Seo W, Yadav RK, Kim J. Quantum chemical calculations of electron affinities of alkaline earth metal atoms (Ca, Sr, Ba, and Ra). J Chem Phys 2024; 160:224307. [PMID: 38856063 DOI: 10.1063/5.0207127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/23/2024] [Indexed: 06/11/2024] Open
Abstract
We performed high-level ab initio quantum chemical calculations, incorporating higher-order excitations, spin-orbit coupling (SOC), and the Gaunt interaction, to calculate the electron affinities (EAs) of alkaline earth (AE) metal atoms (Ca, Sr, Ba, and Ra), which are notably small. The coupled-cluster singles and doubles with perturbative triples [CCSD(T)] method is insufficient to accurately calculate the EAs of AE metal atoms. Higher-order excitations proved crucial, with the coupled-cluster singles, doubles, and triples with perturbative quadruples [CCSDT(2)Q] method effectively capturing dynamic electron correlation effects. The contributions of SOC (ΔESOs) to the EAs calculated using the multireference configuration interaction method with the Davidson correction, including SOC, positively enhance the EAs; however, these contributions are overestimated. The Dirac-Hartree-Fock (DHF)-CCSD(T) method addresses this overestimation and provides reasonable values for ΔESO (ΔESO-D). Employing additional sets of diffuse and core-valence correlation basis sets is critical for accurately calculating the EAs of AE metal atoms. The contributions of the Gaunt interaction (ΔEGaunt) to the EAs of AE metal atoms are negligible. Notably, the CCSDT(2)Q with the complete basis set limit + ΔESO-D + ΔEGaunt produced EA values for Ca, Sr, and Ba that closely aligned with experimental data and achieved accuracy exceeding the chemical accuracy. Based on our findings, the accurately proposed EA for Ra is 9.88 kJ/mol.
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Affiliation(s)
- Eunji Park
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Jeongmin Park
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Ingyeong Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Jungyoon Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Wonil Seo
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Rajesh K Yadav
- Department of Chemistry and Environmental Science, Madan Mohan Malaviya University of Technology, Gorakhpur 273010, U.P., India
| | - Joonghan Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
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9
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Chakraborty R, de Moraes MMF, Boguslawski K, Nowak A, Świerczyński J, Tecmer P. Toward Reliable Dipole Moments without Single Excitations: The Role of Orbital Rotations and Dynamical Correlation. J Chem Theory Comput 2024; 20:4689-4702. [PMID: 38809012 PMCID: PMC11171297 DOI: 10.1021/acs.jctc.4c00471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 05/30/2024]
Abstract
The dipole moment is a crucial molecular property linked to a molecular system's bond polarity and overall electronic structure. To that end, the electronic dipole moment, which results from the electron density of a system, is often used to assess the accuracy and reliability of new electronic structure methods. This work analyses electronic dipole moments computed with the pair coupled cluster doubles (pCCD) ansätze and its linearized coupled cluster (pCCD-LCC) corrections using the canonical Hartree-Fock and pCCD-optimized (localized) orbital bases. The accuracy of pCCD-based dipole moments is assessed against experimental and CCSD(T) reference values using relaxed and unrelaxed density matrices and different basis set sizes. Our test set comprises molecules of various bonding patterns and electronic structures, exposing pCCD-based methods to a wide range of electron correlation effects. Additionally, we investigate the performance of pCCD-in-DFT dipole moments of some model complexes. Finally, our work indicates the importance of orbital relaxation in the pCCD model and shows the limitations of the linearized couple cluster corrections in predicting electronic dipole moments of multiple-bonded systems. Most importantly, pCCD with a linearized CCD correction can reproduce the dipole moment surfaces in singly bonded molecules, which are comparable to the multireference ones.
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Affiliation(s)
- Rahul Chakraborty
- Institute
of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
| | - Matheus Morato F. de Moraes
- Institute
of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
| | - Katharina Boguslawski
- Institute
of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
| | - Artur Nowak
- Institute
of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
| | - Julian Świerczyński
- Institute
of Engineering and Technology, Faculty of Physics, Astronomy, and
Informatics, Nicolaus Copernicus University
in Toruń, Grudzia̧dzka
5, 87-100 Toruń, Poland
| | - Paweł Tecmer
- Institute
of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
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10
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Spencer RJ, Zhanserkeev AA, Yang EL, Steele RP. The Near-Sightedness of Many-Body Interactions in Anharmonic Vibrational Couplings. J Am Chem Soc 2024; 146:15376-15392. [PMID: 38771156 DOI: 10.1021/jacs.4c03198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Couplings between vibrational motions are driven by electronic interactions, and these couplings carry special significance in vibrational energy transfer, multidimensional spectroscopy experiments, and simulations of vibrational spectra. In this investigation, the many-body contributions to these couplings are analyzed computationally in the context of clathrate-like alkali metal cation hydrates, including Cs+(H2O)20, Rb+(H2O)20, and K+(H2O)20, using both analytic and quantum-chemistry potential energy surfaces. Although the harmonic spectra and one-dimensional anharmonic spectra depend strongly on these many-body interactions, the mode-pair couplings were, perhaps surprisingly, found to be dominated by one-body effects, even in cases of couplings to low-frequency modes that involved the motion of multiple water molecules. The origin of this effect was traced mainly to geometric distortion within water monomers and cancellation of many-body effects in differential couplings, and the effect was also shown to be agnostic to the identity of the ion. These outcomes provide new understanding of vibrational couplings and suggest the possibility of improved computational methods for the simulation of infrared and Raman spectra.
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Affiliation(s)
- Ryan J Spencer
- Department of Chemistry and Henry Eyring Center for Theoretical Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Asylbek A Zhanserkeev
- Department of Chemistry and Henry Eyring Center for Theoretical Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Emily L Yang
- Department of Chemistry and Henry Eyring Center for Theoretical Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Ryan P Steele
- Department of Chemistry and Henry Eyring Center for Theoretical Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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11
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Gałyńska M, Boguslawski K. Benchmarking Ionization Potentials from pCCD Tailored Coupled Cluster Models. J Chem Theory Comput 2024; 20:4182-4195. [PMID: 38752491 PMCID: PMC11137826 DOI: 10.1021/acs.jctc.4c00172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/04/2024] [Accepted: 05/07/2024] [Indexed: 05/29/2024]
Abstract
The ionization potential (IP) is an important parameter providing essential insights into the reactivity of chemical systems. IPs are also crucial for designing, optimizing, and understanding the functionality of modern technological devices. We recently showed that limiting the CC ansatz to the seniority-zero sector proves insufficient in predicting reliable and accurate ionization potentials within an IP equation-of-motion coupled-cluster formalism. Specifically, the absence of dynamical correlation in the seniority-zero pair coupled cluster doubles (pCCD) model led to unacceptably significant errors of approximately 1.5 eV. In this work, we aim to explore the impact of dynamical correlation and the choice of the molecular orbital basis (canonical vs localized) in CC-type methods targeting 230 ionized states in 70 molecules, comprising small organic molecules, medium-sized organic acceptors, and nucleobases. We focus on pCCD-based approaches as well as the conventional IP-EOM-CCD and IP-EOM-CCSD. Their performance is compared to the CCSD(T) or CCSDT equivalent and experimental reference data. Our statistical analysis reveals that all investigated frozen-pair coupled cluster methods exhibit similar performance, with differences in errors typically within chemical accuracy (1 kcal/mol or 0.05 eV). Notably, the effect of the molecular orbital basis, such as canonical Hartree-Fock or natural pCCD-optimized orbitals, on the IPs is marginal if dynamical correlation is accounted for. Our study suggests that triple excitations are crucial in achieving chemical accuracy in IPs when modeling electron detachment processes with pCCD-based methods.
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Affiliation(s)
- Marta Gałyńska
- Institute of Physics, Faculty of Physics,
Astronomy, and Informatics, Nicolaus Copernicus
University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
| | - Katharina Boguslawski
- Institute of Physics, Faculty of Physics,
Astronomy, and Informatics, Nicolaus Copernicus
University in Toruń, Grudziadzka 5, 87-100 Toruń, Poland
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12
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Frischknecht AL, Stevens MJ. Force Fields for High Concentration Aqueous KOH Solutions and Zincate Ions. J Phys Chem B 2024; 128:3475-3484. [PMID: 38547112 DOI: 10.1021/acs.jpcb.3c08302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Motivated by increasing interest in electrochemical devices that include highly alkaline electrolytes, we investigated two force fields for potassium hydroxide (KOH) at high concentrations in water. The "FNB" model uses the SPC/E water model, while the "FHM" model uses the TIP4P/2005 water model. We also developed parameters to describe zincate ions in these solutions. The density and viscosity of KOH using the FHM model are in better agreement with experiment than the values from the FNB model. Comparing the properties of the zincate solutions to the available experimental data, we find that both force fields agree reasonably well, although the FHM parameters give a better prediction of the viscosity. The developed force field parameters can be used in future simulations of zincate/KOH solutions in combination with other species of interest.
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Affiliation(s)
- Amalie L Frischknecht
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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13
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Stevens MJ, Rempe SLB. Insight into the K channel's selectivity from binding of K +, Na + and water to N-methylacetamide. Faraday Discuss 2024; 249:195-209. [PMID: 37846738 DOI: 10.1039/d3fd00110e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
In potassium channels that conduct K+ selectively over Na+, which sites are occupied by K+ or water and the mechanism of selectivity are unresolved questions. The combination of the energetics and the constraints imposed by the protein structure yield the selective permeation and occupancy. To gain insight into the combination of structure and energetics, we performed density functional theory (DFT) calculations of multiple N-methyl acetamide (NMA) ligands binding to K+ and Na+, relative to hydrated K+ and Na+. NMA is an analogue of the amino acid backbone and provides the carbonyl binding to the ions that occurs in most binding sites of the K+ channel. Unconstrained optimal structures are obtained through geometry optimization calculations of the NMA ligand binding. The complexes formed by 8 NMA binding to the cations have the O atoms positioned in nearly identical locations as the O atoms in the selectivity filter. The transfer free energies between bulk water and K+ or Na+ bound to 8 NMA are almost identical, implying there is no selectivity by a single site. For water optimized with 8 NMA, binding is weak and O atoms are not positioned as in the K+ channel selectivity filter, suggesting that the ions are much more favored than water. Optimal structures of 8 NMA binding with two cations (K+ or Na+) are stable and have lower binding free energy than the optimal structures with just one cation. However, in the Na+ case, the optimal structure deforms and does not match the K+ channel; that is, two bound Na+ are destabilizing. In contrast, the two K+ structure is stabilized and the selectivity free energy favors K+. Overall, this study shows that binding site occupancy and the mechanism for K+ selectivity involves multiple K+ binding in multiple neighboring layers or sites of the K+ channel selectivity filter.
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Affiliation(s)
- Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA.
| | - Susan L B Rempe
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA.
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14
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Yuan X, Halbert L, Pototschnig JV, Papadopoulos A, Coriani S, Visscher L, Pereira Gomes AS. Formulation and Implementation of Frequency-Dependent Linear Response Properties with Relativistic Coupled Cluster Theory for GPU-Accelerated Computer Architectures. J Chem Theory Comput 2024; 20:677-694. [PMID: 38193434 DOI: 10.1021/acs.jctc.3c00812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
We present the development and implementation of relativistic coupled cluster linear response theory (CC-LR), which allows the determination of molecular properties arising from time-dependent or time-independent electric, magnetic, or mixed electric-magnetic perturbations (within a common gauge origin for the magnetic properties) as well as taking into account the finite lifetime of excited states in the framework of damped response theory. We showcase our implementation, which is capable to offload the computationally intensive tensor contractions characteristic of coupled cluster theory onto graphical processing units, in the calculation of (a) frequency-(in)dependent dipole-dipole polarizabilities of IIB atoms and selected diatomic molecules, with a particular emphasis on the calculation of valence absorption cross sections for the I2 molecule; (b) indirect spin-spin coupling constants for benchmark systems such as the hydrogen halides (HX, X = F-I) as well the H2Se-H2O dimer as a prototypical system containing hydrogen bonds; and (c) optical rotations at the sodium D line for hydrogen peroxide analogues (H2Y2, Y = O, S, Se, Te). Thanks to this implementation, we are able to show the similarities in performance, but often the significant discrepancies, between CC-LR and approximate methods such as density functional theory. Comparing standard CC response theory with the flavor based upon the equation of motion formalism, we find that for valence properties such as polarizabilities, the two frameworks yield very similar results across the periodic table as found elsewhere in the literature; for properties that probe the core region, such as spin-spin couplings, on the other hand, we show a progressive differentiation between the two as relativistic effects become more important. Our results also suggest that as one goes down the periodic table, it may become increasingly difficult to measure pure optical rotation at the sodium D line due to the appearance of absorbing states.
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Affiliation(s)
- Xiang Yuan
- Univ. Lille, CNRS, UMR 8523─PhLAM─Physique des Lasers Atomes et Molécules, F-59000 Lille, France
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Loïc Halbert
- Univ. Lille, CNRS, UMR 8523─PhLAM─Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Johann Valentin Pototschnig
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Anastasios Papadopoulos
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Sonia Coriani
- DTU Chemistry─Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Lucas Visscher
- Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
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15
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Shaaban T, Réal F, Maurice R, Vallet V. Stability of the protactinium(V) mono-oxo cation probed by first-principle calculations. Chemistry 2024:e202304068. [PMID: 38240195 DOI: 10.1002/chem.202304068] [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: 12/06/2023] [Indexed: 02/22/2024]
Abstract
This study explores the distinctive behavior of protactinium (Z=91) within the actinide series. In contrast to neighboring elements like uranium or plutonium, protactinium in the pentavalent state diverges by not forming the typical dioxo protactinyl moiety PaO2 + in aqueous phase. Instead, it manifests as a monooxo PaO3+ cation or a Pa5+ . Employing first-principle calculations with implicit and explicit solvation, we investigate two stoichiometrically equivalent neutral complexes: PaO(OH)2 (X)(H2 O) and Pa(OH)4 (X), where X represents various monodentate and bidentate ligands. Calculating the Gibbs free energy for the reaction PaO(OH)2 (X)(H2 O)→Pa(OH)4 (X), we find that the PaO(OH)2 (X)(H2 O) complex is stabilized with Cl- , Br- , I- , NCS- , NO3 - , and SO4 2- ligands, while it is not favored with OH- , F- , and C2 O4 2- ligands. Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) methods reveal the Pa mono-oxo bond as a triple bond, with significant contributions from the 5f and 6d shells. Covalency of the Pa mono-oxo bond increases with certain ligands, such as Cl- , Br- , I- , NCS- , and NO3 - . These findings elucidate protactinium's unique chemical attributes and provide insights into the conditions supporting the stability of relevant complexes.
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Affiliation(s)
- Tamara Shaaban
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000, Lille, France
| | - Florent Réal
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000, Lille, France
| | - Rémi Maurice
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) -, UMR 6226, F-35000, Rennes, France
| | - Valérie Vallet
- Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000, Lille, France
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16
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Zhang C, Yu P, Conn CJ, Hutzler NR, Cheng L. Relativistic coupled-cluster calculations of RaOH pertinent to spectroscopic detection and laser cooling. Phys Chem Chem Phys 2023; 25:32613-32621. [PMID: 38009218 DOI: 10.1039/d3cp04040b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
A relativistic coupled-cluster study of the low-lying electronic states in the radium monohydroxide molecule (RaOH), a radioactive polyatomic molecule of interest to laser cooling and to the search of new physics beyond the Standard Model, is reported. The level positions of the A2Π1/2 and C2Σ states have been computed with an accuracy of around 200 cm-1 to facilitate spectroscopic observation of RaOH using laser induced fluorescence spectroscopy, thereby exploiting the systematic convergence of electron-correlation and basis-set effects in relativistic coupled-cluster calculations. The energy level for the B2Δ3/2 state has also been calculated accurately to conclude that the B2Δ3/2 state lies above the A2Π1/2 state. This confirms X2Σ ↔ A2Π1/2 as a promising optical cycling transition for laser cooling RaOH.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Phelan Yu
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Chandler J Conn
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Nicholas R Hutzler
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, MD 21218, USA.
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17
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Abstract
The interactions between group 1 and 11 monocations and group 2 dications with triphenylphosphine were studied by using a combination of correlated molecular orbital theory and density functional theory. Two binding modes were found: the front side (phosphorus lone pair) and back side (phenyl rings). Group 1 and 2 cations prefer binding to the π system rather than to the lone pair of the phosphorus atom, and their ligand binding energies (LBEs) correlate with the atomic ionic radii as well as the hardness of the atomic ion. Group 11 monocations prefer binding to the lone pair of the phosphorus atom, and their LBEs are correlated with the hardness of the cation but exhibit a different trend than for the groups 1 and 2 cations. The LBEs of the cations with C2H4, C6H6, and C6H5PH2 are also reported to aid in the analysis of the cation-π interactions and the influence of the PH2 substituent on the energy of this interaction. The LBEs for binding to C2H4 and C6H6 are the most complete and reliable set of values for these species.
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Affiliation(s)
- Damian P Duda
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336, United States
| | - David A Dixon
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487-0336, United States
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18
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Stevens MJ, Rempe SLB. Binding of Li + to Negatively Charged and Neutral Ligands in Polymer Electrolytes. J Phys Chem Lett 2023; 14:10200-10207. [PMID: 37930189 DOI: 10.1021/acs.jpclett.3c02565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Conceptually, single-ion polymer electrolytes (SIPE) with the anion bound to the polymer could solve major issues in Li-ion batteries, but their conductivity is too low. Experimentally, weakly interacting anionic groups have the best conductivity. To provide a theoretical basis for this result, density functional theory calculations of the optimized geometries and energies are performed for charged ligands used in SIPE. Comparison is made to neutral ligands found in dual-ion conductors, which demonstrate higher conductivity. The free energy differences between adding and subtracting a ligand are small enough for the neutral ligands to have the conductivity seen experimentally. However, charged ligands have large barriers, implying that lithium transport will coincide with the slow polymer diffusion, as observed in experiments. Overall, SIPE will require additional solvent to achieve a sufficiently high conductivity. Additionally, the binding of mono- and bidentate geometries varies, providing a simple and clear reason that polarizable force fields are required for detailed interactions.
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Affiliation(s)
- Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Susan L B Rempe
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
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19
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Sharma M, Singh S. Carbon dioxide sequestration in natural gas hydrates - effect of flue and noble gases. Phys Chem Chem Phys 2023; 25:30211-30222. [PMID: 37830431 DOI: 10.1039/d3cp03777k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Clean energy is one of the immediate requirements all over the world to tackle the global energy demands. Natural gas hydrates (NGHs) are one of the proposed alternatives that could be used to extract methane as clean energy and simultaneously sequestrate carbon dioxide. However, the formation of CH4-CO2 mixed hydrates and the first hydrate layer besides the interface reduces the rate of CO2 sequestration and methane extraction in NGHs, and thus, multistep extraction of methane is one of the proposed solutions. We report the atomic level factors that could enhance CO2 sequestration in the newly formed first hydrate layer besides the interface in the presence of flue and noble gases using DFT calculations and molecular dynamics simulations at 250 K and 0.15 kbar. The simulations show the formation of stable dual cages (large-large or small-large) that lead to the formation of a four-caged, Y-shaped cluster (growth synthon) which leads to the formation of a hydrate unit cell in heterogeneous medium. Among the flue and noble gases, only argon forms energetically favorable dual cages with itself and CO2 due to which enhanced CO2 sequestration is observed at different concentrations of Ar and CO2 where the CO2 : Ar (2.5 : 1.5) system shows the best CO2 sequestration in the first layer besides the interface. The results also provide understanding into the previously reported concentration dependent CO2 selectivity in sI hydrates in the presence of third gases (N2 and H2S).
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Affiliation(s)
- Manju Sharma
- School of Chemistry, University of Hyderabad, Hyderabad, 500 046, India.
| | - Satyam Singh
- School of Chemistry, University of Hyderabad, Hyderabad, 500 046, India.
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20
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Stevens MJ, Rempe SLB. Binding of carboxylate and water to monovalent cations. Phys Chem Chem Phys 2023; 25:29881-29893. [PMID: 37889481 DOI: 10.1039/d3cp04200f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
The interactions of carboxylate anions with water and cations are important for a wide variety of systems, both biological and synthetic. To gain insight on properties of the local complexes, we apply density functional theory, to treat the complex electrostatic interactions, and investigate mixtures with varied numbers of carboxylate anions (acetate) and waters binding to monovalent cations, Li+, Na+ and K+. The optimal structure with overall lowest free energy contains two acetates and two waters such that the cation is four-fold coordinated, similar to structures found earlier for pure water or pure carboxylate ligands. More generally, the complexes with two acetates have the lowest free energy. In transitioning from the overall optimal state, exchanging an acetate for water has a lower free energy barrier than exchanging water for an acetate. In most cases, the carboxylates are monodentate and in the first solvation shell. As water is added to the system, hydrogen bonding between waters and carboxylate O atoms further stabilizes monodentate structures. These structures, which have strong electrostatic interactions that involve hydrogen bonds of varying strength, are significantly polarized, with ChelpG partial charges that vary substantially as the bonding geometry varies. Overall, these results emphasize the increasing importance of water as a component of binding sites as the number of ligands increases, thus affecting the preferential solvation of specific metal ions and clarifying Hofmeister effects. Finally, structural analysis correlated with free energy analysis supports the idea that binding to more than the preferred number of carboxylates under architectural constraints are a key to ion transport.
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Affiliation(s)
- Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA.
| | - Susan L B Rempe
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA.
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21
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Sergeieva T, Demirer TI, Wuttke A, Mata RA, Schäfer A, Linker GJ, Andrada DM. Revisiting the origin of the bending in group 2 metallocenes AeCp 2 (Ae = Be-Ba). Phys Chem Chem Phys 2023. [PMID: 37482883 PMCID: PMC10395002 DOI: 10.1039/d2cp05020j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Metallocenes are well-established compounds in organometallic chemistry, and can exhibit either a coplanar structure or a bent structure according to the nature of the metal center (E) and the cyclopentadienyl ligands (Cp). Herein, we re-examine the chemical bonding to underline the origins of the geometry and stability observed experimentally. To this end, we have analysed a series of group 2 metallocenes [Ae(C5R5)2] (Ae = Be-Ba and R = H, Me, F, Cl, Br, and I) with a combination of computational methods, namely energy decomposition analysis (EDA), polarizability model (PM), and dispersion interaction densities (DIDs). Although the metal-ligand bonding nature is mainly an electrostatic interaction (65-78%), the covalent character is not negligible (33-22%). Notably, the heavier the metal center, the stronger the d-orbital interaction with a 50% contribution to the total covalent interaction. The dispersion interaction between the Cp ligands counts only for 1% of the interaction. Despite that orbital contributions become stronger for heavier metals, they never represent the energy main term. Instead, given the electrostatic nature of the metallocene bonds, we propose a model based on polarizability, which faithfully predicts the bending angle. Although dispersion interactions have a fair contribution to strengthen the bending angle, the polarizability plays a major role.
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Affiliation(s)
- Tetiana Sergeieva
- Department of Chemistry, Saarland University, Campus Saarbrücken, 66123 Saarbrücken, Germany.
| | - T Ilgin Demirer
- Department of Chemistry, Saarland University, Campus Saarbrücken, 66123 Saarbrücken, Germany.
| | - Axel Wuttke
- Institute for Physical Chemistry, Georg-August-University Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany.
| | - Ricardo A Mata
- Institute for Physical Chemistry, Georg-August-University Göttingen, Tammannstrasse 6, D-37077 Göttingen, Germany.
| | - André Schäfer
- Department of Chemistry, Saarland University, Campus Saarbrücken, 66123 Saarbrücken, Germany.
| | - Gerrit-Jan Linker
- MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, The Netherlands.
| | - Diego M Andrada
- Department of Chemistry, Saarland University, Campus Saarbrücken, 66123 Saarbrücken, Germany.
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22
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Changala PB, Genossar-Dan N, Brudner E, Gur T, Baraban JH, McCarthy MC. Structural and electronic trends of optical cycling centers in polyatomic molecules revealed by microwave spectroscopy of MgCCH, CaCCH, and SrCCH. Proc Natl Acad Sci U S A 2023; 120:e2303586120. [PMID: 37399375 PMCID: PMC10334755 DOI: 10.1073/pnas.2303586120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 05/23/2023] [Indexed: 07/05/2023] Open
Abstract
The unique optical cycling efficiency of alkaline earth metal-ligand molecules has enabled significant advances in polyatomic laser cooling and trapping. Rotational spectroscopy is an ideal tool for probing the molecular properties that underpin optical cycling, thereby elucidating the design principles for expanding the chemical diversity and scope of these platforms for quantum science. We present a comprehensive study of the structure and electronic properties in alkaline earth metal acetylides with high-resolution microwave spectra of 17 isotopologues of MgCCH, CaCCH, and SrCCH in their 2Σ+ ground electronic states. The precise semiexperimental equilibrium geometry of each species has been derived by correcting the measured rotational constants for electronic and zero-point vibrational contributions calculated with high-level quantum chemistry methods. The well-resolved hyperfine structure associated with the 1,2H, 13C, and metal nuclear spins provides further information on the distribution and hybridization of the metal-centered, optically active unpaired electron. Together, these measurements allow us to correlate trends in chemical bonding and structure with the electronic properties that promote efficient optical cycling essential to next-generation experiments in precision measurement and quantum control of complex polyatomic molecules.
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Affiliation(s)
- P. Bryan Changala
- Atomic and Molecular Physics Division, Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA02138
| | - Nadav Genossar-Dan
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva8410501, Israel
| | - Ella Brudner
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva8410501, Israel
| | - Tomer Gur
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva8410501, Israel
| | - Joshua H. Baraban
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva8410501, Israel
| | - Michael C. McCarthy
- Atomic and Molecular Physics Division, Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA02138
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23
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Zhang C, Hutzler NR, Cheng L. Intensity-Borrowing Mechanisms Pertinent to Laser Cooling of Linear Polyatomic Molecules. J Chem Theory Comput 2023. [PMID: 37384588 DOI: 10.1021/acs.jctc.3c00408] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
A study of the intensity-borrowing mechanisms important to optical cycling transitions in laser-coolable polyatomic molecules arising from non-adiabatic coupling, contributions beyond the Franck-Condon approximation, and Fermi resonances is reported. It has been shown to be necessary to include non-adiabatic coupling to obtain computational accuracy that is sufficient to be useful for laser cooling of molecules. The predicted vibronic branching ratios using perturbation theory based on the non-adiabatic mechanisms have been demonstrated to agree well with those obtained from variational discrete variable representation calculations for representative molecules including CaOH, SrOH, and YbOH. The electron-correlation and basis-set effects on the calculated transition properties, including the vibronic coupling constants, the spin-orbit coupling matrix elements, and the transition dipole moments, and on the calculated branching ratios have been thoroughly studied. The vibronic branching ratios predicted using the present methodologies demonstrate that RaOH is a promising radioactive molecule candidate for laser cooling.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Nicholas R Hutzler
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, United States
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
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24
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Chan B. Compilation of Ionic Clusters with the Rock Salt Structure: Accurate Benchmark Thermochemical Data, Assessment of Quantum Chemistry Methods, and the Convergence Behavior of Lattice Energies. J Phys Chem A 2023. [PMID: 37368538 DOI: 10.1021/acs.jpca.3c01880] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
In the present study, computational quantum chemistry is used to obtain lattice energies (LEs) for a range of ionic clusters with the NaCl structure. Specifically, the compounds include NaF, NaCl, MgO, MgS, KF, CaO, and CaS clusters, (MX)n, with n = 1, 2, 4, 6, 8, 12, 16, 24, 32, 40, 50, 60, 75, 90, and 108. The highest-level W2 and W1X-2 methods are applied to the small clusters with n = 1 to 8 (the MX35 data set). The assessment with MX35 shows that, for the calculation of geometries and vibrational frequencies, the PBE0-D3(BJ) and PBE-D3(BJ) DFT methods are reasonable, but the calculation of atomization energies is more challenging. This is a result of different systematic deviations for clusters of different species. Thus, species-specific adjustments are applied for larger clusters, which are calculated with the DuT-D3 double-hybrid DFT method, the MN15 DFT method, and the PM7 semi-empirical method. They yield smoothly converging LEs to the bulk values. It is also found that, for the alkali-metal species, the LEs for a single molecule are ∼70% of the bulk values, while for the alkali-earth species, they are ∼80%. This has enabled a straightforward means to the first-principles estimation of LEs for similarly structured ionic compounds.
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Affiliation(s)
- Bun Chan
- Graduate School of Engineering, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan
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25
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Peng J, Wang L, Wang P, Pei Y. Density Functional Theory Computation and Machine Learning Studies of Interaction between Au 3 Clusters and 20 Natural Amino Acid Molecules. ACS OMEGA 2023; 8:23024-23031. [PMID: 37396243 PMCID: PMC10308543 DOI: 10.1021/acsomega.3c02195] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 05/17/2023] [Indexed: 07/04/2023]
Abstract
The optimal adsorption sites and the binding energies of neutral Au3 clusters with 20 natural amino acids under the gas phase and water solvation were systematically investigated based on density functional theory (DFT) calculations. The calculation results showed that in the gas phase Au3 tends to bind with N atoms of amino groups in amino acids, except methionine, which tends to bind with Au3 through S atoms. Under water solvation, Au3 clusters tended to bind to N atoms of amino groups and N atoms of side chain amino groups in amino acids. However, methionine and cysteine bind more strongly to the gold atom through the S atom. Based on the binding energy data of Au3 clusters and 20 natural amino acids under water solvation calculated by DFT, a machine learning model (gradient boosted decision tree) was proposed to predict the optimal binding Gibbs free energy (ΔG) of the interaction between Au3 clusters and amino acids. The main factors affecting the strength of the interaction between Au3 and amino acids were uncovered by the feature importance analysis.
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Affiliation(s)
- Jiao Peng
- Department
of Chemistry, Key Laboratory for Green Organic Synthesis and Application
of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry
and Applications of Ministry of Education, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Li Wang
- Department
of Chemistry, Key Laboratory for Green Organic Synthesis and Application
of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry
and Applications of Ministry of Education, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Pu Wang
- Department
of Chemistry, Key Laboratory for Green Organic Synthesis and Application
of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry
and Applications of Ministry of Education, Xiangtan University, Xiangtan, Hunan 411105, China
| | - Yong Pei
- Department
of Chemistry, Key Laboratory for Green Organic Synthesis and Application
of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry
and Applications of Ministry of Education, Xiangtan University, Xiangtan, Hunan 411105, China
- School
of Minerals Processing and Bioengineering, Central South University, Changsha, Hunan 410083, China
- State
Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming 650093, China
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26
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Szczepkowski J, Gronowski M, Grochola A, Jastrzebski W, Tomza M, Kowalczyk P. Excited Electronic States of Sr 2: Ab Initio Predictions and Experimental Observation of the 2 1Σ u+ State. J Phys Chem A 2023; 127:4473-4482. [PMID: 37192534 DOI: 10.1021/acs.jpca.3c02056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Despite its apparently simple nature with four valence electrons, the strontium dimer constitutes a challenge for modern electronic structure theory. Here we focus on excited electronic states of Sr2, which we investigate theoretically up to 25000 cm-1 above the ground state, to guide and explain new spectroscopic measurements. In particular, we focus on potential energy curves for the 11Σu+, 21Σu+, 11Πu, 21Πu, and 11Δu states computed using several variants of ab initio coupled-cluster and configuration-interaction methods to benchmark them. In addition, a new experimental study of the excited 21Σu+ state using polarization labeling spectroscopy is presented, which extends knowledge of this state to high vibrational levels, where perturbation by higher electronic states is observed. The available experimental observations are compared with the theoretical predictions and help to assess the accuracy and limitations of employed theoretical models. The present results pave the way for future more accurate theoretical and experimental spectroscopic studies.
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Affiliation(s)
- Jacek Szczepkowski
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Marcin Gronowski
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - Anna Grochola
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
| | | | - Michał Tomza
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - Paweł Kowalczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
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27
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Woińska M, Pawlędzio S, Chodkiewicz ML, Woźniak K. Hirshfeld Atom Refinement of Metal-Organic Complexes: Treatment of Hydrogen Atoms Bonded to Transition Metals. J Phys Chem A 2023; 127:3020-3035. [PMID: 36947670 PMCID: PMC10084459 DOI: 10.1021/acs.jpca.2c06998] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Hydrogen positions in hydrides play a key role in hydrogen storage materials and high-temperature superconductors. Our recently published study of five crystal structures of transition-metal-bound hydride complexes showed that using aspherical atomic scattering factors for Hirshfeld atom refinement (HAR) resulted in a systematic elongation of metal-hydrogen bonds compared to using spherical scattering factors with the Independent Atom Model (IAM). Even though only standard-resolution X-ray data was used, for the highest-quality data, we obtained excellent agreement between the X-ray and the neutron-derived bond lengths. We present an extended version of this study including 10 crystal structures of metal-organic complexes containing hydrogen atoms bonded to transition-metal atoms for which both X-ray and neutron data are available. The neutron structures were used as a benchmark, and the X-ray structures were refined by applying Hirshfeld atom refinement using various basis sets and DFT functionals in order to investigate the influence of the technical aspects on the length of metal-hydrogen bonds. The result of including relativistic effects in the Hamiltonian and using a cluster of multipoles simulating interactions with a crystal environment during wave function calculations was examined. The effect of the data quality on the final result was also evaluated. The study confirms that a high quality of experimental data is the key factor allowing us to obtain significant improvement in transition metal (TM)-hydrogen bond lengths from HAR in comparison with the IAM. Individual adjustments and better choices of the basis set can improve hydrogen positions. Average differences between TM-H bond lengths obtained with various DFT functionals upon including relativistic effects or between double-ζ and triple-ζ basis sets were not statistically significant. However, if all bonds formed by H atoms were considered, significant differences caused by different refinement strategies were observed. Finally, we examined the refinement of atomic thermal motions. Anisotropic refinement of hydrogen thermal motions with HAR was feasible only in some cases, and isotropically refined hydrogen thermal motions were in similar agreement with neutron values whether obtained with HAR or with the IAM.
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Affiliation(s)
- Magdalena Woińska
- Biological and Chemical Research Centre, Chemistry Department, University of Warsaw, Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Sylwia Pawlędzio
- Biological and Chemical Research Centre, Chemistry Department, University of Warsaw, Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Michał L Chodkiewicz
- Biological and Chemical Research Centre, Chemistry Department, University of Warsaw, Żwirki i Wigury 101, 02-089 Warszawa, Poland
| | - Krzysztof Woźniak
- Biological and Chemical Research Centre, Chemistry Department, University of Warsaw, Żwirki i Wigury 101, 02-089 Warszawa, Poland
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28
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Shirkov L, Tomza M. Long-range interactions of aromatic molecules with alkali-metal and alkaline-earth-metal atoms. J Chem Phys 2023; 158:094109. [PMID: 36889959 DOI: 10.1063/5.0135929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The isotropic and anisotropic coefficients Cn l,m of the long-range spherical expansion ∼1/Rn (R-the intermolecular distance) of the dispersion and induction intermolecular energies are calculated using the first principles for the complexes containing an aromatic molecule (benzene, pyridine, furan, and pyrrole) and alkali-metal (Li, Na, K, Rb, and Cs) or alkaline-earth-metal (Be, Mg, Ca, Sr, and Ba) atoms in their electronic ground states. The values of the first- and second-order properties of the aromatic molecules are calculated using the response theory with the asymptotically corrected LPBE0 functional. The second-order properties of the closed-shell alkaline-earth-metal atoms are obtained using the expectation-value coupled cluster theory and of the open-shell alkali-metal atoms using analytical wavefunctions. These properties are used for the calculation of the dispersion Cn,disp l,m and induction Cn,ind l,m coefficients (Cn l,m=Cn,disp l,m+Cn,ind l,m) with n up to 12 using the available implemented analytical formulas. It is shown that the inclusion of the coefficients with n > 6 is important for reproducing the interaction energy in the van der Waals region at R ≈ 6 Å. The reported long-range potentials should be useful for constructing the analytical potentials valid for the whole intermolecular interaction range, which are needed for spectroscopic and scattering studies.
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Affiliation(s)
- Leonid Shirkov
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Michał Tomza
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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29
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Majumder R, Sokolov AY. Simulating Spin-Orbit Coupling with Quasidegenerate N-Electron Valence Perturbation Theory. J Phys Chem A 2023; 127:546-559. [PMID: 36599072 DOI: 10.1021/acs.jpca.2c07952] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We present the first implementation of spin-orbit coupling effects in fully internally contracted second-order quasidegenerate N-electron valence perturbation theory (SO-QDNEVPT2). The SO-QDNEVPT2 approach enables the computations of ground- and excited-state energies and oscillator strengths combining the description of static electron correlation with an efficient treatment of dynamic correlation and spin-orbit coupling. In addition to SO-QDNEVPT2 with the full description of one- and two-body spin-orbit interactions at the level of two-component Breit-Pauli Hamiltonian, our implementation also features a simplified approach that takes advantage of spin-orbit mean-field approximation (SOMF-QDNEVPT2). The accuracy of these methods is tested for the group 14 and 16 hydrides, 3d and 4d transition metal ions, and two actinide dioxides (neptunyl and plutonyl dications). The zero-field splittings of group 14 and 16 molecules computed using SO-QDNEVPT2 and SOMF-QDNEVPT2 are in good agreement with the available experimental data. For the 3d transition metal ions, the SO-QDNEVPT2 method is significantly more accurate than SOMF-QDNEVPT2, while no substantial difference in the performance of two methods is observed for the 4d ions. Finally, we demonstrate that for the actinide dioxides the results of SO-QDNEVPT2 and SOMF-QDNEVPT2 are in good agreement with the data from previous theoretical studies of these systems. Overall, our results demonstrate that SO-QDNEVPT2 and SOMF-QDNEVPT2 are promising multireference methods for treating spin-orbit coupling with a relatively low computational cost.
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Affiliation(s)
- Rajat Majumder
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
| | - Alexander Yu Sokolov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio43210, United States
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30
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Kłos J, Tiesinga E. Elastic and glancing-angle rate coefficients for heating of ultracold Li and Rb atoms by collisions with room-temperature noble gases, H 2, and N 2. J Chem Phys 2023; 158:014308. [PMID: 36610981 DOI: 10.1063/5.0124062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Trapped ultracold alkali-metal atoms can be used to measure pressure in the ultra-high-vacuum and XHV pressure regimes, those with p < 10-6 Pa. This application for ultracold atoms relies on precise knowledge of collision rate coefficients of alkali-metal atoms with residual room-temperature atoms and molecules in the ambient vacuum or with deliberately introduced gasses. Here, we determine combined elastic and inelastic rate coefficients as well as glancing-angle rate coefficients for ultracold 7Li and 87Rb with room-temperature noble gas atoms as well as H2 and 14N2 molecules. Glancing collisions are those processes where only little momentum is transferred to the alkali-metal atom and this atom is not ejected from its trap. Rate coefficients are found by performing quantum close-coupling scattering calculations using ab initio ground-state electronic Born-Oppenheimer potential energy surfaces. The potentials for Li and Rb with noble gas atoms and also for Rb(2S)-H2(XΣg +) and Rb(2S)-N2(X1Σg +) systems are based on the non-relativistic spin-restricted coupled-cluster method with single, double, and noniterative triple excitations [RCCSD(T)]. For Li(2S)-N2(X1Σg +), the potential is computed at the explicitly correlated spin-restricted RCCSD(T)-F12 level. For Rb, Kr, and Xe atoms, scalar relativistic corrections to the core electrons have been included, while second-order spin-orbit corrections from the valence electrons have been estimated. Data for Li-H2 and Li-He were taken from the existing literature. We estimate standard uncertainties of the rate coefficients by comparing rate coefficients calculated using potentials found with electronic basis sets of increasing size, including estimates of relativistic spin-orbit corrections and the uncertainty of the van der Waals coefficients. The relative uncertainties of rate coefficients are 1%-2% with the exception of 7Li or 87Rb colliding with 20Ne. Those have relative uncertainties of 9% and 8%, respectively. We also show that a commonly used semiclassical approximation for the total elastic rate coefficient agrees with the quantum calculations to 10% with the exception of 7Li and 87Rb collisions with H2, where the semiclassical value underestimates the quantum value by 20%.
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Affiliation(s)
- Jacek Kłos
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Eite Tiesinga
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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31
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Xiao H, Wang J, Zhang R, Shan N, Gao T. The vibrational and hyperfine spectroscopy toward laser cooling 87Sr 35Cl. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 282:121679. [PMID: 35917619 DOI: 10.1016/j.saa.2022.121679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/23/2022] [Accepted: 07/24/2022] [Indexed: 06/15/2023]
Abstract
We theoretically investigate the possibility of laser cooling 87Sr35Cl molecule in accordance with vibrational and hyperfine spectroscopy. The potential energy curves and dipole moment of the X2Σ+1/2, A2Π1/2,3/2 and B2Σ+ states are calculated using ab initio method and the spectroscopic parameters are in good agreement with the experimental data. On account of the accurate potential energy curves and the transition dipole moment, the Franck - Condon factors and radiative lifetimes are predicted. Comparing the conditions of laser cooling candidate molecules, the A2Π 1/2 ↔ X2Σ+1/2 transition is selected as the laser cooling cycle system. In order to obtain an approximately closed cooling cycle system, we employed matrix element algorithm to calculated the hyperfine spectroscopy and branching ratios of the 87Sr35Cl molecule. Furthermore, an electro-optical modulator (EOM) is designed including six hyperfine levels of the ground state X2Σ+1/2 (v = 0, N = 1).
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Affiliation(s)
- Huagang Xiao
- Institute of Atomic and Molecular physics, Sichuan University, Chengdu 610065, China
| | - Jiangnan Wang
- Institute of Atomic and Molecular physics, Sichuan University, Chengdu 610065, China
| | - Ruijie Zhang
- Institute of Atomic and Molecular physics, Sichuan University, Chengdu 610065, China
| | - Na Shan
- Institute of Atomic and Molecular physics, Sichuan University, Chengdu 610065, China
| | - Tao Gao
- Institute of Atomic and Molecular physics, Sichuan University, Chengdu 610065, China; Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, China.
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32
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Liu Y, Huang J, Yang D, Xie D, Guo H. Global Full-Dimensional Potential Energy Surface for the Reaction 23Na 87Rb + 23Na 87Rb → 23Na 2 + 87Rb 2 and the Formation Rate and Lifetime of the 23Na 287Rb 2 Collision Complex. J Phys Chem A 2022; 126:9008-9021. [DOI: 10.1021/acs.jpca.2c06438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Yilang Liu
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Jing Huang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
| | - Dongzheng Yang
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
- Hefei National Laboratory, Hefei 230088, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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33
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Dempsey SH, Kass SR. Liberating the Anion: Evaluating Weakly Coordinating Cations. J Org Chem 2022; 87:15466-15482. [DOI: 10.1021/acs.joc.2c02001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Stephen H. Dempsey
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Steven R. Kass
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
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34
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Gong P, An L, Tong J, Liu X, Liang Z, Li J. Design of A-D-A-Type Organic Third-Order Nonlinear Optical Materials Based on Benzodithiophene: A DFT Study. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12203700. [PMID: 36296890 PMCID: PMC9611063 DOI: 10.3390/nano12203700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 05/31/2023]
Abstract
The acceptor-donor-acceptor (A-D-A) type conjugated organic molecule has been widely applied in the organic optoelectronics field. A total of Nine compounds (1-9) were designed under the A-D-A framework, with the electron donor benzodithiophene as the core and dicyanomethylene as the acceptor moiety, modifying the benzodithiophene with the phenyl, naphthyl, and difluorinated phenyl groups. The conjugation length can be changed by introducing a thiophene π-conjugated bridge. The geometric structures, electronic structure, excited state properties, aromaticity, and the static- and frequency-dependent second hyperpolarizabilities were investigated by employing high-precision density functional theory (DFT) calculations with an aug-cc-pVDZ basis set. As a result, the three compounds with the longest conjugation length exhibit a smaller energy gap (Egap), larger UV-vis absorption coefficient, and response range, which are the three strongest third-order nonlinear optical (NLO) response properties in this work. This work systematically explored the connection between molecular structure and NLO response, which provides a rational design strategy for high-performance organic NLO materials.
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Affiliation(s)
- Pingping Gong
- Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Lili An
- Key Laboratory of Optoelectronic Technology and Intelligent Control of Ministry Education, Lanzhou Jiaotong University, Lanzhou 730070, China
- School of Chemical Engineering, Northwest Minzu University, Lanzhou 730030, China
| | - Junfeng Tong
- Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Xinpeng Liu
- Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Zezhou Liang
- Key Laboratory of Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Photonic Technique for Information, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China
| | - Jianfeng Li
- Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
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35
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ZORA Gaussian basis sets for Fr, Ra, and Ac. J Mol Model 2022; 28:334. [PMID: 36171413 DOI: 10.1007/s00894-022-05331-4] [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: 06/21/2022] [Accepted: 09/21/2022] [Indexed: 10/14/2022]
Abstract
Segmented all-electron basis sets of double and triple zeta valence qualities plus polarization functions (DZP and TZP) for the elements Fr, Ra, and Ac to be used with the zeroth-order regular approximation (ZORA) were presented. These sets were constructed from the reoptimization of the contraction coefficients of the corresponding non-relativistic basis sets. In order to adequately describe electrons distant from the atomic nuclei, these sets were augmented with diffuse functions and were, respectively, designated as ADZP-ZORA and ATZP-ZORA. At the ZORA-B3LYP theory level, the relativistic sets were employed to calculate ionization energies of Fr, Ra, and Ac as well as bond lengths, dissociation energies, harmonic vibrational frequencies, and static mean dipole polarizabilities of some diatomics. Comparing with benchmark theoretical results and with experimental data available in the literature, it can be verified that our basis sets are able to produce reliable and accurate results. Evaluation of the performances of ZORA and second-order Douglas-Kroll-Hess Hamiltonians was performed.
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36
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Hachani L, Khadri F, Hammami K. New theoretical investigation of rotational inelastic (de)-excitation of calcium isocyanide CaNC( 2Σ +) in collision with He( 1S). Phys Chem Chem Phys 2022; 24:24212-24218. [PMID: 36169045 DOI: 10.1039/d2cp02485c] [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 theoretical study of collisions between atoms and molecules provides a detailed description of the involved mechanisms and greatly contributes to improving atmospheric and astrophysics models. In the present paper, we focus on the new calculation of rate coefficients for the first 25 rotational levels of the CaNC molecule in collision with He. A new 2D potential energy surface (2D-PES), for the CaNC-He system, was determined using the single, double and perturbative triple excitation restricted coupled-cluster method [rccsd(t)] and the standard aug-cc-pVQZ basis sets. This PES presents a global minimum with a well depth of -21.93 cm-1 located at R = 8a0 and γ = 116°. State-to-state collisional excitation cross-sections of the fine-structure levels of CaNC(2Σ+)-He are calculated for energies up to 305 cm-1, which yield, after thermal averaging, rate coefficients up to 70 K. A ΔJ = ΔN propensity rule was observed. A comparison of the CaNC rates with those of valence isoelectronic MgNC has been investigated. These new data are necessary for the CaNC abundance determination and interpretation of its observed lines.
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Affiliation(s)
| | - Fehmi Khadri
- LSAMA, Université Tunis El-Manar, Tunis, Tunisia.
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37
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Stevens MJ, Rempe SLB. Carboxylate binding prefers two cations to one. Phys Chem Chem Phys 2022; 24:22198-22205. [PMID: 36093927 DOI: 10.1039/d2cp03561h] [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
Almost all studies of specific ion binding by carboxylates (-COO-) have considered only a single cation, but clustering of ions and ligands is a common phenomenon. We apply density functional theory to investigate how variations in the number of acetate ligands in binding to two monovalent cations affects ion binding preferences. We study a series of monovalent (Li+, Na+, K+, Cs+) ions relevant to experimental work on many topics, including ion channels, battery storage, water purification and solar cells. We find that the preferred optimal structure has 3 acetates except for Cs+, which has 2 acetates. The optimal coordination of the cation by the carboxylate O atoms is 4 for both Na+ and K+, and 3 for Li+ and Cs+. There is a 4-fold coordination minimum just a few kcal mol-1 higher than the optimal 3-fold structure for Li+. For two cations, multiple minima occur in the vicinity of the lowest free energy state. We find that, for Li, Na and K, the preferred optimal structure with two cations is favored over a mixture of single cation complexes, providing a basis for understanding ionic cluster formation that is relevant for engineering proteins and other materials for rapid, selective ion transport.
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Affiliation(s)
- Mark J Stevens
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA.
| | - Susan L B Rempe
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM 87185, USA. .,CBRN Defense and Energy Technologies, Sandia National Laboratories, Albuquerque, NM, 87185, USA.
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38
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Eliyahu-Caspi G, Makov G, Rosenwaks S, Barmashenko BD. Dissociative Recombination of K 2+ and Rb 2+ in Diode-Pumped Alkali Lasers: Potential Energy Curves and Atomic Products. J Phys Chem A 2022; 126:5751-5760. [PMID: 35994326 DOI: 10.1021/acs.jpca.2c05096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dissociative recombination (DR) of K2+ and Rb2+ ions is one of the most important processes in K and Rb diode-pumped alkali lasers (DPALs) strongly affecting their power. We report on the calculations of potential energy curves of the K2+ and Rb2+ molecular ions and of the diabatic 1Σ+, 3Σ+, 1Δ, 3Δ, 1Π, 3Π, 1Φ, and 3Φ valence states of K2 and Rb2 that provide the routes for DR of the ions. These curves are required for subsequent calculations of DR rate constants. It was found that the most likely DR routes for K are along the dissociative states 61Σg+, 53Σu+, and 23Δu and for Rb only 61Σg+. The excited states of K atoms produced by DR are 42P and 52P. Most of the Rb atoms produced by DR are in the 62P excited state, while a small fraction of the atoms produced by the less likely routes along two states of Rb2 are in the 52P state. This conclusion contradicts the kinetic scheme for K and Rb DPAL proposed elsewhere, and thus the kinetic schemes of these DPALs should be modified according to the present results.
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Affiliation(s)
- Gilead Eliyahu-Caspi
- Department of Materials Engineering, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel.,Department of Physics, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Guy Makov
- Department of Materials Engineering, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Salman Rosenwaks
- Department of Physics, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
| | - Boris D Barmashenko
- Department of Physics, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 8410501, Israel
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39
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Hill AN, Meijer AJHM, Hill JG. Correlation Consistent Basis Sets and Core Polarization Potentials for Al-Ar with ccECP Pseudopotentials. J Phys Chem A 2022; 126:5853-5863. [PMID: 35976118 PMCID: PMC9442647 DOI: 10.1021/acs.jpca.2c04446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
New correlation consistent basis sets for the second-row
atoms
(Al–Ar) to be used with the neon-core correlation consistent
effective core potentials (ccECPs) have been developed. The basis
sets, denoted cc-pV(n+d)Z-ccECP (n = D, T, Q), include the “tight”-d functions that are
known to be important for second-row elements. Sets augmented with
additional diffuse functions are also reported. Effective core polarization
potentials (CPPs) to account for the effect of core–valence
correlation have been adjusted for the same elements, and two different
forms of the CPP cutoff function have been analyzed. The accuracy
of both the basis sets and the CPPs is assessed through benchmark
calculations at the coupled-cluster level of theory for atomic and
molecular properties. Agreement with all-electron results is much
improved relative to the basis sets that originally accompanied the
ccECPs; moreover, the combination of cc-pV(n+d)Z-ccECP
and CPPs is found to be a computationally efficient and accurate alternative
to including core electrons in the correlation treatment.
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Affiliation(s)
- Adam N Hill
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Anthony J H M Meijer
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - J Grant Hill
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
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40
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Mato J, Tzeli D, Xantheas SS. The Many-Body Expansion for Metals I: The Alkaline Earth metals Be, Mg, and Ca. J Chem Phys 2022; 157:084313. [DOI: 10.1063/5.0094598] [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
We examine the Many-Body Expansion (MBE) for alkaline earth metal clusters, Be n, Mg n, Ca n ( n = 4, 5, 6) at the MP2, CCSD(T), MRPT2, and MRCI levels of theory. The magnitude of each term in the MBE is evaluated for several geometrical configurations. We find that the behavior of the MBE for these clusters depends strongly on the geometrical arrangement, and, to a lesser extent, on the level of theory used. Another factor that affects the MBE is the in situ (ground or excited) electronic state of the individual atoms in the cluster. For most geometries, the three-body term is the largest, followed by a steady decrease in absolute energy for subsequent terms. Though these systems exhibit non-negligible multi-reference effects, there was little qualitative difference in the MBE expansion when employing single vs. multi-reference methods. Useful insights into the connectivity and stability of these clusters have been drawn from the respective potential energy surfaces and Quasi-Atomic orbitals for the various dimers, trimers, and tetramers. Through these analyses we investigate the similarities and differences in the binding energies of different size clusters for these metals.
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Affiliation(s)
- Joani Mato
- Chemical Physics, Pacific Northwest National Laboratory, United States of America
| | - Demeter Tzeli
- Department of Chemistry, National and Kapodistrian University of Athens Department of Chemistry, Greece
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41
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Kulsha AV, Ragoyja EG, Ivashkevich OA. Strong Bases Design: Predicted Limits of Basicity. J Phys Chem A 2022; 126:3642-3652. [PMID: 35657384 DOI: 10.1021/acs.jpca.2c00521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Brønsted superbases have wide applications in organic chemistry due to their ability to activate C-H bonds. The strongest neutral bases to date are substituted aminophosphazenes developed in the late 1980s by Reinhard Schwesinger. Since then, much effort has been expended to create even stronger neutral bases. In this article, the reasons for the instability of very basic compounds are investigated by means of high-level quantum-chemical calculations. Theoretical basicity limits are suggested for solutions as well as for the gas phase. A record-breaking superbase most likely to be synthesizable and stable at ambient conditions is proposed. Hexamethylphosphoramide is considered a reliable ionizing solvent for superbases.
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Affiliation(s)
- Andrey V Kulsha
- Chemical Department, Belarusian State University, 4 Nezavisimosti Avenue, 220030 Minsk, Republic of Belarus
| | - Ekaterina G Ragoyja
- Chemical Department, Belarusian State University, 4 Nezavisimosti Avenue, 220030 Minsk, Republic of Belarus
| | - Oleg A Ivashkevich
- Laboratory for Chemistry of Condensed Systems, Research Institute for Physical Chemical Problems of the Belarusian State University, 14 Leningradskaya Street, 220006 Minsk, Republic of Belarus
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42
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Jellali S, Habli H. Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr 2, Fr-AEM + (AEM= Ca, Sr, Ba)]. J Phys Chem A 2022; 126:3613-3628. [PMID: 35670472 DOI: 10.1021/acs.jpca.1c10801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The experimental field of ultracold ion-atom mixtures including an alkali-metal atom and an alkaline-earth-metal ion as well as of homonuclear alkali dimers has paved the way for creating and manipulating the ultracold molecules. The present paper is focused on a study of molecules such us francium dimer and a comparative spectroscopic investigation of the cationic systems Fr-(Ca+, Sr+, Ba+). We adopt a computational scheme without spin-orbit coupling reposed on the full configuration interaction and semi-empirical pseudo-potential theory of the atomic cores Fr+, Ca2+, Sr2+, and Ba2+ with extended and optimized basis sets. We have determined the adiabatic potentials with their relative spectroscopic constants, the electric dipole moments and the vibrational levels spacings for the 1,3Σu,g+ and 1,3Σ+ electronic states for Fr2 and Fr-AEM+, respectively, correlated toward {Fr(7s) + Fr(7s, 7p, 6d, 8s, 8p)}, {Ca(4s2, 4s4p, 4s3d), Sr(5s2, 5s5p, 5s4d), Ba(6s2, 6s6p, 6s5d) + Fr+}, and {Ca+(4s, 3d), Sr+(5s, 4d), Ba+(6s, 5d) + Fr(7s, 7p)}. The accuracy and reliability of the current results are discussed by comparing with theoretical data available in the literature. The occurrence of some avoided crossings between the neighboring electronic states is leading to a charge or excitation transfer for atom-ion collisions in the diverse charge or excited states. The Σ+-Σ+ transitions are determined in order to evaluate the future radiative lifetimes of vibrational states serving the direct laser cooling.
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Affiliation(s)
- Soulef Jellali
- Faculté des Sciences de Monastir, Laboratoire de Physique Quantique et Statistique, Université de Monastir, Avenue de l'Environnement, Monastir 5019, Tunisie
| | - Héla Habli
- Faculté des Sciences de Monastir, Laboratoire de Physique Quantique et Statistique, Université de Monastir, Avenue de l'Environnement, Monastir 5019, Tunisie.,Institut Supérieur des Sciences Appliquées et de Technologie de Sousse, Université de Sousse, Rue ibn Khaldun, Cité Taffala, Sousse 4003, Tunisie
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43
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Ghosh A, Banerjee S, Sarkar S, Debnath T, Ash T, Roy RS, Das AK. Energetics and Spectroscopic Properties of Low‐lying CaC
6
H
2
Isomers: An Astrochemical Perspective. ChemistrySelect 2022. [DOI: 10.1002/slct.202200763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Avik Ghosh
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Soumadip Banerjee
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Subhendu Sarkar
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Tanay Debnath
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Tamalika Ash
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Ria Sinha Roy
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
| | - Abhijit K. Das
- School of Mathematical and Computational Sciences, Indian Association for the Cultivation of Science, Jadavpur Kolkata 700032 India
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44
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Tkachenko NV, Rublev P, Boldyrev AI, Lehn JM. Superalkali Coated Rydberg Molecules. Front Chem 2022; 10:880804. [PMID: 35494656 PMCID: PMC9043523 DOI: 10.3389/fchem.2022.880804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
A series of complexes of Na, K, NH4, and H3O with [bpy.bpy.bpy]cryptand, [2.2.2]cryptand, and spherical cryptand were investigated via DFT and ab initio methods. We found that by coating Rydberg molecules with the “organic skin” one could further decrease their ionization potential energy, reaching the values of ∼1.5 eV and a new low record of 1.3 eV. The neutral cryptand complexes in this sense possess a weakly bounded electron and may be considered as very strong reducing agents. Moreover, the presence of an organic cage increases the thermodynamic stability of Rydberg molecules making them stable toward the proton detachment.
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Affiliation(s)
- Nikolay V. Tkachenko
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Pavel Rublev
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
| | - Alexander I. Boldyrev
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, United States
- *Correspondence: Alexander I. Boldyrev,
| | - Jean-Marie Lehn
- Laboratoire de Chimie Supramoléculaire, Institut de Science et d’Ingénierie, Supramoléculaires Université de Strasbourg, Strasbourg, France
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45
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Krumins V, Kruzins A, Tamanis M, Ferber R, Meshkov V, Pazyuk E, Stolyarov AV, Pashov AE. Observation and modelling of bound-free transitions to the $X^1\Sigma^+$ and $a^3\Sigma^+$ states of KCs. J Chem Phys 2022; 156:114305. [DOI: 10.1063/5.0082309] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Valts Krumins
- University of Latvia Faculty of Physics Mathematics and Optometry, Latvia
| | | | - Maris Tamanis
- University of Latvia Faculty of Physics Mathematics and Optometry, Latvia
| | - Ruvin Ferber
- Faculty of Physics, Mathematics and Optometry, University of Latvia Faculty of Physics Mathematics and Optometry, Latvia
| | - Vladimir Meshkov
- Department of Chemistry, Lomonosov Moscow State University, Russia
| | | | | | - Asen Enev Pashov
- Optics and spectroscopy, Sofia University, Faculty of Physics, Bulgaria
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46
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Kumar R, Ghosh A, Vaval N. Decay Processes in Cationic Alkali Metals in Microsolvated Clusters: A Complex Absorbing Potential Based Equation-of-Motion Coupled Cluster Investigation. J Chem Theory Comput 2022; 18:807-816. [PMID: 35019266 DOI: 10.1021/acs.jctc.1c01036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have employed the highly accurate complex absorbing potential based ionization potential equation-of-motion coupled cluster singles and doubles (CAP-IP-EOM-CCSD) method to study the various intermolecular decay processes in ionized metals (Li+, Na+, K+) microsolvated by water molecules. For the Li atom, the electron is ionized from the 1s subshell. However, for Na and K atoms, the electron is ionized from 2s and both 2s and 2p subshells, respectively. We have investigated decay processes for the Li+-(H2O)n (n = 1-3) systems, as well as Na+-(H2O)n (n = 1, 2), and K+-H2O. The lithium cation in water can decay only via electron transfer mediated decay (ETMD) as there are no valence electrons in lithium. We have investigated how the various decay processes change in the presence of different alkali metal atoms and how the increasing number of water molecules play a significant role in the decay of microsolvated systems. To see the effect of the environment, we have studied Li+-NH3 in comparison to Li+-H2O. In the case of Na+-H2O, we have studied the impact of bond distance on the decay width. The effect of polarization on decay width was checked for the X+-H2O (X = Li, Na) systems. We used the PCM model to study the polarization effect. We have compared our results with existing theoretical and experimental results wherever available in the literature.
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Affiliation(s)
- Ravi Kumar
- Academy of Scientific and Innovative Research, CSIR-Human Resource Development Center (CSIR-HRDC) Campus, Postal Staff College Area, Ghaziabad, Uttar Pradesh 201002, India.,Electronic Structure Theory Group, Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Aryya Ghosh
- Department of Chemistry, Ashoka University, Sonipat, Haryana 131029, India
| | - Nayana Vaval
- Electronic Structure Theory Group, Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
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47
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Osika Y, Shundalau M. Fock-space relativistic coupled cluster study on the RaF molecule promising for the laser cooling. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 264:120274. [PMID: 34438114 DOI: 10.1016/j.saa.2021.120274] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/05/2021] [Accepted: 08/08/2021] [Indexed: 06/13/2023]
Abstract
The potential energy curves of the ground and five low-lying excited terms of the RaF molecule are calculated using the Fock-space relativistic coupled theory. The electronic term energies, equilibrium internuclear distances, transition and permanent dipole moments, sequences of vibrational energies, harmonic vibrational frequencies, Franck-Condon factors, and radiative lifetimes are predicted. The calculated spectroscopic constants are in good agreement with the available theoretical and experimental data. The scheme for the direct laser cooling involving the first excited A2П1/2 state is proposed. The data obtained in this study suggests the A2П1/2 → X2Σ+ channel in the RaF molecule is the almost ideal case for direct laser cooling. It is quite possible that the effective cooling scheme for the RaF molecule can be realized using only one pump laser.
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Affiliation(s)
- Yuliya Osika
- Faculty of Physics, Belarusian State University, 4 Nezaležnaści Ave., Minsk 220030, Belarus
| | - Maksim Shundalau
- Faculty of Physics, Belarusian State University, 4 Nezaležnaści Ave., Minsk 220030, Belarus.
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48
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Ariyarathna IR. Ground and Electronically Excited States of Main-Group-Metal-Doped B 20 Double Rings. J Phys Chem A 2021; 126:506-512. [PMID: 34939805 DOI: 10.1021/acs.jpca.1c08631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Ab initio coupled-cluster, electron propagator, and Møller-Plesset second-order perturbation theory calculations are utilized to analyze the low-lying electronic states of several metal-doped B20. In the ground state, the presently focused AB20/EB20 (A = Li, Na, and K; E = Mg and Ca) consist of charge-separated A+B20-/E2+B202- frameworks. The excited electronic states of AB20 and EB20+ were analyzed by computing the vertical electron attachment energies (VEAEs) of AB20+ and EB202+. In several excited states, the radical electron is predominantly localized on the B20 frames, which are counterparts of the low-lying states of bare B20-. A variety of basis sets were tested on obtaining VEAEs, and the aug-cc-pVDZ/A,E d-aug-cc-pVDZ/B combination provided the best accuracy-efficiency compromise on them. Furthermore, this work analyzes the Rydberg-like excited states of AB20 and EB20+ and will serve as a guide for future studies on similar metal-doped boron systems.
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Affiliation(s)
- Isuru R Ariyarathna
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312, United States
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49
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Rock CA, Arradondo SN, Tschumper GS. Solvation of Isoelectronic Halide and Alkali Metal Ions by Argon Atoms. J Phys Chem A 2021; 125:10524-10531. [PMID: 34851634 DOI: 10.1021/acs.jpca.1c08069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This work systematically examines the interactions of alkali metal cations and their isoelectronic halide counterparts with up to six solvating Ar atoms (M+Arn and X-Arn, where M = Li, Na, K, and Rb; X = H, F, Cl, and Br; and n = 1-6) via full geometry optimizations with the MP2 method and robust, correlation-consistent quadruple-ζ (QZ) basis sets. 116 unique M+Arn and X-Arn stationary points have been characterized on the MP2/QZ potential energy surface. To the best of our knowledge, approximately two dozen of these stationary points have been reported here for the first time. Some of these new structures are either the lowest-energy stationary point for a particular cluster or energetically competitive with it. The CCSD(T) method was employed to perform additional single-point energy computations upon all MP2/QZ-optimized structures using the same basis set. CCSD(T)/QZ results indicate that internally solvated structures with the ion at/near the geometric center of the cluster have appreciably higher energies than those placing the ion on the periphery. While this study extends the prior investigations of M+Arn clusters found within the literature, it notably provides one of the first thorough characterizations of and comparisons to the corresponding negatively charged X-Arn clusters.
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Affiliation(s)
- Carly A Rock
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
| | - Sarah N Arradondo
- Department of Chemistry, Washington College, Chestertown, Maryland 21620-1438, United States
| | - Gregory S Tschumper
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
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50
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Rizkallah GC, Assaf AA, Tohme SN. Molecular structure and properties of MgCa molecule. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2021.111316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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