1
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Watrous AG, Fortenberry RC. The fundamental vibrational frequencies and spectroscopic constants of the C 2O 2H 2 isomers: molecules known in simulated interstellar ice analogues. Phys Chem Chem Phys 2024. [PMID: 39076036 DOI: 10.1039/d4cp02201g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
While trans-glyoxal may not be easily observable in astronomical sources through either IR or radioastronomy due to its C2h symmetry, its cis conformer along with the cyc-H2COCO epoxide isomer should be ready targets for astrochemical detection. The present quantum chemical study shows that not only are both molecular isomers strongly polar, they also have notable IR features and low isomerisation energies of 4.1 kcal mol-1 and 10.7 kcal mol-1, respectively. These three isomers along with two other C2O2H2 isomers have had their full set of fundamental vibrational frequencies and spectroscopic constants characterised herein. These isomers have previously been shown to occur in simulated astrophysical ices making them worthy targets of astronomical search. Furthermore, the hybrid quartic force field (QFF) approach utilized herein to produce the needed spectral data has a mean absolute percent error compared to the experimentally-available, gas phase fundamental vibrational frequencies of 0.6% and rotational constants to better than 0.1%. The hybrid QFF is defined from explicitly correlated coupled cluster theory at the singles, doubles, and perturbative triples level [CCSD(T)-F12b] including core electron correlation and a canonical CCSD(T) relativity correction for the harmonic (quadratic) terms in the QFF and simple CCSD(T)-F12b/cc-pVDZ energies for the cubic and quartic terms, the so-called "F12-TcCR+DZ QFF." This method is producing spectroscopically-accurate predictions for both fundamental vibrational frequencies and principal spectroscopic constants. Hence, the values computed in this work should be notably accurate and, hence, exceptionally useful to the spectroscopy and astrochemistry communities.
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2
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Denis-Alpizar O, Zanchet A, Stoecklin T. Quantum study of the rovibrational relaxation of HF by collision with 4He on a new potential energy surface. Phys Chem Chem Phys 2024; 26:13432-13440. [PMID: 38647242 DOI: 10.1039/d3cp05606f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
The HF molecule is considered the main reservoir of fluorine in the interstellar medium (ISM). Also, the interactions of this molecule with the most common atoms and molecules in the ISM have attracted great interest from the astrochemical community. Collisions between HF and helium have recently caused controversy following a study using a two-dimensional SAPT potential energy surface (PES) that exhibited large discrepancies with previous scattering calculations based on more recent ab initio potentials. To address this issue, our current work aims to develop the most precise three-dimensional PES for the HF+He system. We employ the size-consistent CCSD(T) method in conjunction with the aug-cc-pV6Z basis set. The main features of the new PES as well as the bound states of the He-HF complex are compared to the existing data. The new PES is then utilised to conduct close coupling calculations that demonstrate He-HF as a good instance of vibration-rotation near resonant energy transfer. The novel rate coefficients will be accessible via the BASECOL database, and the use of the new PES is advised when describing HF in helium droplets.
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Affiliation(s)
- Otoniel Denis-Alpizar
- Departamento de Física, Facultad de Ciencias, Universidad de Chile, Av. Las Palmeras 3425, Ñuñoa, Santiago, Chile.
| | - Alexandre Zanchet
- Instituto de Fsica Fundamental, CSIC, Serrano 123, 28006, Madrid, Spain.
| | - Thierry Stoecklin
- Institut des Sciences Moleculaires, Universite de Bordeaux, CNRS UMR 5255, 33405 Talence Cedex, France.
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3
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Maxson T, Szilvási T. Transferable Water Potentials Using Equivariant Neural Networks. J Phys Chem Lett 2024; 15:3740-3747. [PMID: 38547514 DOI: 10.1021/acs.jpclett.4c00605] [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
Machine learning interatomic potentials (MLIPs) have emerged as a technique that promises quantum theory accuracy for reduced cost. It has been proposed [J. Chem. Phys. 2023, 158, 084111] that MLIPs trained on solely liquid water data cannot accurately transfer to the vapor-liquid equilibrium while recovering the many-body decomposition (MBD) analysis of gas-phase water clusters. This suggests that MLIPs do not directly learn the physically correct interactions of water molecules, limiting transferability. In this work, we show that MLIPs using equivariant architecture and trained on 3200 liquid water structures reproduces liquid-phase water properties (e.g., density within 0.003 g/cm3 between 230 and 365 K), vapor-liquid equilibrium properties up to 550 K, the MBD analysis of gas-phase water cluster up to six-body interactions, and the relative energy and the vibrational density of states of ice phases. We show that potentials developed using equivariant MLIPs allow transferability for arbitrary phases of water that remain stable in nanosecond long simulations.
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Affiliation(s)
- Tristan Maxson
- Department of Chemical and Biological Engineering, University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Tibor Szilvási
- Department of Chemical and Biological Engineering, University of Alabama, Tuscaloosa, Alabama 35487, United States
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4
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Fortenberry RC. Quantum Chemistry and Astrochemistry: A Match Made in the Heavens. J Phys Chem A 2024; 128:1555-1565. [PMID: 38381079 DOI: 10.1021/acs.jpca.3c07601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Quantum chemistry can uniquely answer astrochemical questions that no other technique can provide. Computations can be parallelized, automated, and left to run continuously providing exceptional molecular throughput that cannot be done through experimentation. Additionally, the granularity of the individual computations that are required of potential energy surfaces, reaction mechanism pathways, or other quantum chemically derived observables produces a unique mosaic that make up the larger whole. These pieces can be dissected for their individual contributions or evaluated in an ad hoc fashion for each of their roles in generating the larger whole. No other scientific approach is capable of reporting such fine-grained insights. Quantum chemistry also works from a bottom-up approach in providing properties directly from the desired molecule instead of a top-down perspective as required of experiment where molecules have to be linked to observed phenomena. Furthermore, modern quantum chemistry is well within the range of "chemical accuracy" and is approaching "spectroscopic accuracy." As such, the seemingly difficult questions asked by astrochemistry that would not be asked initially for any other application require quantum chemical reference data. While the results of quantum chemical computations are needed to interpret astrochemical observation, modeling, or laboratory experimentation, such hard questions, regardless of the original need to answer them, produce unique solutions. While questions in astrochemistry often require novel developments in and implementations of quantum chemistry as outlined herein, the applications of these solutions will stretch beyond astrochemistry and may yet impact fields much closer to Earth.
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Affiliation(s)
- Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, Oxford, Mississippi 38677-1848, United States
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5
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Garrett NR, Davis MC, Fortenberry RC. DFT + F12 QFFs for Cost-Effective Rovibrational Spectral Data Predictions of Ground and Excited Electronic States. J Chem Theory Comput 2024. [PMID: 38230913 DOI: 10.1021/acs.jctc.3c01179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The quest for faster computation of anharmonic vibrational frequencies of both ground and excited electronic states has led to combining coupled cluster theory harmonic force constants with density functional theory cubic and quartic force constants for defining a quartic force field (QFF) utilized in conjunction with vibrational perturbation theory at second order (VPT2). This work shows that explicitly correlated coupled cluster theory at the singles, doubles, and perturbative triples levels [CCSD(T)-F12] provides accurate anharmonic vibrational frequencies and rotational constants when conjoined with any of B3LYP, CAM-B3LYP, BHandHLYP, PBE0, and ωB97XD for roughly one-quarter of the computational time of the CCSD(T)-F12 QFF alone for our test set. As the number of atoms in the molecule increases, however, the anharmonic terms become a greater portion of the QFF, and the cost comparison improves with HOCO+ and formic acid, requiring less than 15 and 10% of the time, respectively. In electronically excited states, PBE0 produces more consistently accurate results. Additionally, as the size of the molecule and, in turn, QFF increase, the cost savings for utilizing such a hybrid approach for both ground- and excited-state computations grows. As such, these methods are promising for predicting accurate rovibrational spectral properties for electronically excited states. In cases where well-behaved potentials for a small selection of targeted excited states are needed, such an approach should reduce the computational cost compared to that of methods requiring semiglobal potential surfaces or variational treatments of the rovibronic Hamiltonian. Such applications include spectral characterization of comets, exoplanets, or any situation in which gas phase molecules are being excited by UV-vis radiation.
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Affiliation(s)
- Noah R Garrett
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
| | - Megan C Davis
- Theoretical Division, T-1, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
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6
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Gorges J, Grimme S, Hansen A, Pracht P. Towards understanding solvation effects on the conformational entropy of non-rigid molecules. Phys Chem Chem Phys 2022; 24:12249-12259. [PMID: 35543018 DOI: 10.1039/d1cp05805c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The absolute molecular entropy is a fundamental quantity for the accurate description of thermodynamic properties. For non-rigid molecules, a substantial part of the entropy can be attributed to a conformational contribution. Systems and properties where this is relevant, e.g., protein-ligand binding affinities or pKa values refer usually to the liquid phase. In this work, the influence of solvation on the conformational entropy is investigated. A recently introduced state-of-the-art and automated computational protocol for the computation of conformational entropies [Pracht et al., Chem. Sci., 2021, 12, 6551-6568.] is applied in combination with fast and accurate semiempirical quantum-chemical methods and implicit solvation models for a set of 25 commercially available drug molecules and five transition metal compounds. Computed gas-phase conformational entropies are compared with values obtained in implicit n-hexane and water. It is found that implicit solvation can have a substantial effect of several cal mol-1 K-1 on the entropy as a result of large conformational changes in the different phases. We conclude that for flexible molecules chemical accuracy for free energies in solution can only be achieved if solvation effects on the conformational ensemble are considered.
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Affiliation(s)
- Johannes Gorges
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115 Bonn, Germany.
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115 Bonn, Germany.
| | - Andreas Hansen
- Mulliken Center for Theoretical Chemistry, Institute for Physical and Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115 Bonn, Germany.
| | - Philipp Pracht
- Institute for Physical Chemistry, RWTH Aachen University, Melatener Str. 20, 52056 Aachen, Germany.
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7
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Mihm TN, Schäfer T, Ramadugu SK, Weiler L, Grüneis A, Shepherd JJ. A shortcut to the thermodynamic limit for quantum many-body calculations of metals. NATURE COMPUTATIONAL SCIENCE 2021; 1:801-808. [PMID: 38217186 PMCID: PMC10766528 DOI: 10.1038/s43588-021-00165-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 10/26/2021] [Indexed: 01/15/2024]
Abstract
Computationally efficient and accurate quantum mechanical approximations to solve the many-electron Schrödinger equation are crucial for computational materials science. Methods such as coupled cluster theory show potential for widespread adoption if computational cost bottlenecks can be removed. For example, extremely dense k-point grids are required to model long-range electronic correlation effects, particularly for metals. Although these grids can be made more effective by averaging calculations over an offset (or twist angle), the resultant cost in time for coupled cluster theory is prohibitive. We show here that a single special twist angle can be found using the transition structure factor, which provides the same benefit as twist averaging with one or two orders of magnitude reduction in computational time. We demonstrate that this not only works for metal systems but also is applicable to a broader range of materials, including insulators and semiconductors.
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Affiliation(s)
- Tina N Mihm
- Department of Chemistry, University of Iowa, Iowa City, Iowa, USA
| | - Tobias Schäfer
- Institute for Theoretical Physics, TU Wien, Vienna, Austria
| | | | - Laura Weiler
- Department of Chemistry, University of Iowa, Iowa City, Iowa, USA
| | | | - James J Shepherd
- Department of Chemistry, University of Iowa, Iowa City, Iowa, USA.
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8
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Welch BK, Almeida NMS, Wilson AK. Super ccCA (s-ccCA): an approach for accurate transition metal thermochemistry. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1963001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Bradley K. Welch
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Nuno M. S. Almeida
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
| | - Angela K. Wilson
- Department of Chemistry, Michigan State University, East Lansing, MI, USA
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9
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Li H, Brémond E, Sancho-García JC, Adamo C. Pairing double hybrid functionals with a tailored basis set for an accurate thermochemistry of hydrocarbons. RSC Adv 2021; 11:26073-26082. [PMID: 35479441 PMCID: PMC9037073 DOI: 10.1039/d1ra04108h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/19/2021] [Indexed: 11/21/2022] Open
Abstract
A collection of five challenging datasets, including noncovalent interactions, reaction barriers and electronic rearrangements of medium-sized hydrocarbons, has been selected to verify the robustness of double-hybrid functionals used in conjunction with the small DH-SVPD basis set, especially developed for noncovalent interactions. The analysis is completed by other, more standard functionals, for a total of 17 models, including also empirical corrections for dispersion. The obtained results show that the chemical accuracy threshold, that is an error lower than 1.0 kcal mol−1, can be obtained by pairing the nonempirical PBE-QIDH functional with the DH-SVPD basis set, as well as by other semi-empirical functionals, such as DSD-PBEP86, using larger basis sets and empirical corrections. More in general, a significant improvement can be obtained using the DH-SVPD basis set with DHs, without resorting to any empirical corrections. This choice leads to a fast computational protocol that, avoiding any empirical potential, remains on a fully quantum ground. The pairing of the PBE-QIDH double-hybrid functional with a tailored split-valence basis set leads to a fast computational protocol for the accurate evaluation of hydrocarbon thermochemistry, without resorting to any empirical correction.![]()
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Affiliation(s)
- Hanwei Li
- Chimie ParisTech, PSL Research University, CNRS, Institute of Chemistry for Health and Life Sciences F-75005 Paris France
| | - Eric Brémond
- Université de Paris, ITODYS, CNRS F-75006 Paris France
| | | | - Carlo Adamo
- Chimie ParisTech, PSL Research University, CNRS, Institute of Chemistry for Health and Life Sciences F-75005 Paris France .,Institut Universitaire de France 103 Boulevard Saint Michel F-75005 Paris France
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10
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Schäfer T, Daelman N, López N. Cerium Oxides without U: The Role of Many-Electron Correlation. J Phys Chem Lett 2021; 12:6277-6283. [PMID: 34212726 PMCID: PMC8397342 DOI: 10.1021/acs.jpclett.1c01589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/29/2021] [Indexed: 05/14/2023]
Abstract
Electron transfer with changing occupation in the 4f subshell poses a considerable challenge for quantitative predictions in quantum chemistry. Using the example of cerium oxide, we identify the main deficiencies of common parameter-dependent one-electron approaches, such as density functional theory (DFT) with a Hubbard correction, or hybrid functionals. As a response, we present the first benchmark of ab initio many-electron theory for electron transfer energies and lattice parameters under periodic boundary conditions. We show that the direct random phase approximation clearly outperforms all DFT variations. From this foundation, we, then, systematically improve even further. Periodic second-order Møller-Plesset perturbation theory meanwhile manages to recover standard hybrid functional values. Using these approaches to eliminate parameter bias allows for highly accurate benchmarks of strongly correlated materials, the reliable assessment of various density functionals, and functional fitting via machine-learning.
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Affiliation(s)
- Tobias Schäfer
- Institute
for Theoretical Physics, TU Wien, Wiedner Hauptstraße 8-10/136, 1040 Vienna, Austria
| | - Nathan Daelman
- Institute
of Chemical Research of Catalonia, The Barcelona
Institute of Science and Technology, 43007 Tarragona, Spain
| | - Núria López
- Institute
of Chemical Research of Catalonia, The Barcelona
Institute of Science and Technology, 43007 Tarragona, Spain
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11
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Fortenberry RC, DeYonker NJ. Rovibrational Quantum Chemical Treatment of Inorganic and Organometallic Astrochemicals. Acc Chem Res 2021; 54:271-279. [PMID: 33356121 DOI: 10.1021/acs.accounts.0c00631] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ConspectusOur two groups have both independently and collaboratively been pushing quantum-chemical techniques to produce highly accurate predictions of anharmonic vibrational frequencies and spectroscopic constants for molecules containing atoms outside of the typical upper p block. Methodologies employ composite approaches, relying on various levels of coupled cluster theory-most often at the singles, doubles, and perturbative triples level-and quartic force field constructions of the potential portion of the intramolecular Watson Hamiltonian. Such methods are known to perform well for organic species, and we have extended this to molecules containing atoms outside of this realm.One notable atom that has received much attention in this application is magnesium. Mg is the second-most-abundant element in the Earth's mantle, and while molecules containing this element are among the confirmed astrochemicals, its further atomic abundance in the galaxy implies that many more molecules (both purely inorganic and organometallic) containing element 12 exist in astrophysical regions in chemical sizes between those of atoms and dust-sized nanocrystals. Our approach discussed herein is producing quality benchmarks and predicting novel data for magnesium-bearing molecules.The story is similar for Al and Si, which are also notably abundant in both rocky bodies and the universe at large. While Na, Sc, and Cu may not be as abundant as Mg, Al, and Si, molecules containing Na and transition metals have also previously been reported to be detected beyond the Earth. Consequently, the need to produce spectral reference data for molecules containing such atoms is growing. While several experimental groups (including, notably, the groups in Arizona, Boston, and France/Spain) have clearly led the way in detection of inorganic/organometallic molecules in space, computational support and even rational design can provide novel avenues for the detection of molecules containing atoms not typically studied in most laboratories. The application of quantum chemistry to other elements beyond carbon and its cronies at the top right of the periodic table promises a better understanding of the observable universe. It will also provide novel and fundamental chemical insights pushing the "central science" into new molecular territory.
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Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848, United States
| | - Nathan J. DeYonker
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States
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12
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Sorathia K, Tew DP. Basis set extrapolation in pair natural orbital theories. J Chem Phys 2020; 153:174112. [PMID: 33167642 DOI: 10.1063/5.0022077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the results of a benchmark study of the effect of Pair Natural Orbital (PNO) truncation errors on the performance of basis set extrapolation. We find that reliable conclusions from the application of Helgaker's extrapolation method are only obtained when using tight PNO thresholds of at least 10-7. The use of looser thresholds introduces a significant risk of observing a false basis set convergence and underestimating the residual basis set errors. We propose an alternative extrapolation approach based on the PNO truncation level that only requires a single basis set and show that it is a viable alternative to hierarchical basis set extrapolation methods.
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Affiliation(s)
- Kesha Sorathia
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, GermanyUniversity of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - David P Tew
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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13
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Kiessling AJ, Cina JA. Exploring a spectral filtering approach to electronic structure calculations. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1827178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Alexis J. Kiessling
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
- Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon, USA
| | - Jeffrey A. Cina
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
- Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon, USA
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14
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Fortenberry RC, Wiesenfeld L. A Molecular Candle Where Few Molecules Shine: HeHHe . Molecules 2020; 25:molecules25092183. [PMID: 32392765 PMCID: PMC7249080 DOI: 10.3390/molecules25092183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 12/03/2022] Open
Abstract
HeHHe+ is the only potential molecule comprised of atoms present in the early universe that is also easily observable in the infrared. This molecule has been known to exist in mass spectrometry experiments for nearly half-a-century and is likely present, but as-of-yet unconfirmed, in cold plasmas. There can exist only a handful of plausible primordial molecules in the epochs before metals (elements with nuclei heavier than 4He as astronomers call them) were synthesized in the universe, and most of these are both rotationally and vibrationally dark. The current work brings HeHHe+ into the discussion as a possible (and potentially only) molecular candle for probing high-z and any metal-deprived regions due to its exceptionally bright infrared feature previously predicted to lie at 7.43 μm. Furthermore, the present study provides new insights into its possible formation mechanisms as well as marked stability, along with the decisive role of anharmonic zero-point energies. A new entrance pathway is proposed through the triplet state (3B1) of the He2H+ molecule complexed with a hydrogen atom and a subsequent 10.90 eV charge transfer/photon emission into the linear and vibrationally-bright 1Σg+ HeHHe+ form.
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Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, University, MS 38677-1848, USA
- Correspondence: ; Tel.: +1-662-915-1687
| | - Laurent Wiesenfeld
- Laboratoire Aimé-Cotton, CNRS & Université Paris-Saclay, 91405 Orsay, France;
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15
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Mohammadi A, Nasiri S, Zahedi M. Coupled Cluster and Quantum Monte-Carlo study of anionic hydrogen clusters Hn-3≤n(odd)≤11. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Niu Z, Tang M, Ge N. Structure, stability, infrared spectra, and bonding of OH m(H 2O) 7 ( m = 0, ±1) clusters: ab initio study combining the particle swarm optimization algorithm. Phys Chem Chem Phys 2020; 22:26487-26501. [PMID: 33185201 DOI: 10.1039/d0cp04332j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The various structural candidates of anionic, neutral, and cationic water clusters OHm(H2O)7 (m = 0, ±1) have been globally predicted by combining the particle swarm optimization method and quantum chemical calculations. Geometry optimization and vibrational analysis for the optimal structures were performed with the MP2/aug-cc-pVDZ method, and the energy profile was further refined at the CCSD(T)/CBS level. Special attention was paid to the relationships between configurations and energies, particularly the first solvation shell coordination number of OH- and OH. For OH-(H2O)7, OH(H2O)7, and OH+(H2O)7 clusters, the most stable species at room temperature are predicted to be the tetra-solvated multi-ring structure A6, the tri-solvated hemibond cage structure N1, and the single five-membered ring structure C2, respectively. The temperature effects on the stability of these three systems were also explored via Gibbs free energies. Furthermore, for the OH-(H2O)7 clusters, the assignments of vibrational transitions in the OH stretching region are in good agreement with the studies of small hydroxide ion-water clusters, and the IR spectra of two isomers (tetra-solvated multi-ring A6 and penta-solvated cage A3) may match future experimental observation well. By topological analysis and reduced density gradient analysis, the structural characteristics and bonding strengths of the studied clusters were investigated. This work indicates the excellent performance of the PSO search algorithm and CALYPSO on water clusters, and may further provide extensive insights into the chemical behavior such as the transport mechanism of OH- ions and OH radicals in the aqueous phase.
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Affiliation(s)
- Zhenwei Niu
- School of National Defense Science & Technology, Southwest University of Science and Technology, Mianyang 621010, P. R. China
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17
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The performance of explicitly correlated wavefunctions [CCSD(T)-F12b] in the computation of anharmonic vibrational frequencies. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.136720] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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18
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Nikolaienko TY, Chuiko VS, Bulavin LA. The dataset of covalent bond lengths resulting from the first-principle calculations. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.112508] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Piccini G, Parrinello M. Accurate Quantum Chemical Free Energies at Affordable Cost. J Phys Chem Lett 2019; 10:3727-3731. [PMID: 31244270 DOI: 10.1021/acs.jpclett.9b01301] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Free energy sampling methods allow studying the full dynamics of activated processes. Unfortunately, the affordable accuracy of the potential describing the energy and forces of the system is usually rather low. Here we introduce a new method that by combining metadynamics and free energy perturbation allows calculating accurate quantum chemical free energies for chemical reactions. To prove the effectiveness of this new approach we study the SN2 reaction of CH3F + Cl- → CH3Cl + F- in vacuo and solvated by water. Comparisons are made with harmonic transition-state theory to show how this method could provide accurate equilibrium and rate constants for complex systems.
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Affiliation(s)
- GiovanniMaria Piccini
- Department of Chemistry and Applied Biosciences , ETH Zurich , c/o USI Campus, Via Giuseppe Buffi 13 , CH-6900 Lugano , Switzerland
- Facoltà di Informatica, Istituto di Scienze Computazionali , Università della SvizzeraItaliana (USI) , Via Giuseppe Buffi 13 , CH-6900 Lugano , Switzerland
| | - Michele Parrinello
- Department of Chemistry and Applied Biosciences , ETH Zurich , c/o USI Campus, Via Giuseppe Buffi 13 , CH-6900 Lugano , Switzerland
- Facoltà di Informatica, Istituto di Scienze Computazionali , Università della SvizzeraItaliana (USI) , Via Giuseppe Buffi 13 , CH-6900 Lugano , Switzerland
- Istituto Italiano di Tecnologia , Via Morego 30 , 16163 Genova , Italy
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20
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Nutho B, Mulholland AJ, Rungrotmongkol T. Quantum Mechanics/Molecular Mechanics (QM/MM) Calculations Support a Concerted Reaction Mechanism for the Zika Virus NS2B/NS3 Serine Protease with Its Substrate. J Phys Chem B 2019; 123:2889-2903. [PMID: 30845796 DOI: 10.1021/acs.jpcb.9b02157] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Zika virus (ZIKV) is mainly transmitted to humans by Aedes species mosquitoes and is associated with serious pathological disorders including microcephaly in newborns and Guillain-Barré syndrome in adults. Currently, there is no vaccine or anti-ZIKV drug available for preventing or controlling ZIKV infection. An attractive drug target for ZIKV treatment is a two-compartment (NS2B/NS3) serine protease that processes viral polyprotein during infection. Here, conventional molecular dynamics simulations of the ZIKV protease in complex with peptide substrate (TGKRS) sequence at the C-terminus of NS2B show that the substrate is in the active conformation for the cleavage reaction by ZIKV protease. Hybrid quantum mechanics/molecular mechanics (QM/MM) umbrella sampling simulations (PM6/ff14SB) of acylation results reveal that proton transfer from S135 to H51 and nucleophilic attack on the substrate by S135 are concerted. The rate-limiting step involves the formation of a tetrahedral intermediate. In addition, the single-point energy QM/MM calculations, precisely at the level of coupled cluster theory (LCCSD(T)/(aug)-cc-pVTZ), were performed to correct the potential energy profiles for the first step of the acylation process. The average computed activation barrier at this level of theory is 16.3 kcal mol-1. Therefore, the computational approaches presented here are helpful for further designing of NS2B/NS3 inhibitors based on transition-state analogues.
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Affiliation(s)
| | - Adrian J Mulholland
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
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21
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Ren J, Zhao D, Wu SJ, Wang J, Jia YJ, Li WX, Zhu HJ, Cao F, Li W, Pittman CU, He XJ. Reassigning the stereochemistry of bioactive cepharanthine using calculated versus experimental chiroptical spectroscopies. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.01.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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22
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Fortenberry RC, Lee TJ. Computational vibrational spectroscopy for the detection of molecules in space. ANNUAL REPORTS IN COMPUTATIONAL CHEMISTRY 2019. [DOI: 10.1016/bs.arcc.2019.08.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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23
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Tsatsoulis T, Sakong S, Groß A, Grüneis A. Reaction energetics of hydrogen on Si(100) surface: A periodic many-electron theory study. J Chem Phys 2018; 149:244105. [DOI: 10.1063/1.5055706] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Theodoros Tsatsoulis
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
- Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - Sung Sakong
- Institute of Theoretical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Axel Groß
- Institute of Theoretical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Andreas Grüneis
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany
- Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
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24
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Fortenberry RC, Novak CM, Lee TJ, Bera PP, Rice JE. Identifying Molecular Structural Aromaticity for Hydrocarbon Classification. ACS OMEGA 2018; 3:16035-16039. [PMID: 31458241 PMCID: PMC6643553 DOI: 10.1021/acsomega.8b02734] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/15/2018] [Indexed: 06/10/2023]
Abstract
Determination of aromaticity in hydrocarbons may be as simple as determining the average bond length for the molecule of interest. This would greatly assist in classifying the nature of hydrocarbon chemistry, especially for large molecules such as polycyclic aromatic hydrocarbons (PAHs) where today's aromatic classification methods are prohibitively expensive. The average C-C bond lengths for a test set of known aromatic, antiaromatic, and aliphatic cyclic hydrocarbons are computed here, and they show strong delineating patterns for the structural discernment of these aromaticity classifications. Aromatic molecules have average C-C bond lengths of 1.41 Å or less with the largest molecules, PAHs, having the longest average C-C bond lengths; aliphatic species have such lengths of 1.50 Å or more; and antiaromatic species fall between the two. Consequently, a first-order guess as to the aromaticity of a system may simply arise from its geometry. Although this prediction will likely have exceptions, such simple screening can easily classify most cases, and more advanced techniques can be brought to bear on the cases that lie in the boundaries. Benchmarks for hydrocarbons are provided here, but other classes of molecular structural aromaticity likely will have to be defined on an ad hoc basis.
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Affiliation(s)
- Ryan C. Fortenberry
- Department
of Chemistry & Biochemistry, University
of Mississippi, University, Mississippi 38655-1848, United States
| | - Carlie M. Novak
- Department
of Chemistry & Biochemistry, Georgia
Southern University, Statesboro, Georgia 30460, United States
| | - Timothy J. Lee
- MS
245-3 NASA Ames Research Center, Moffett Field, California 94035-1000, United States
| | - Partha P. Bera
- Bay
Area Environmental Research Institute, Petaluma, California 94952, United States
| | - Julia E. Rice
- IBM
Almaden Research Center, IBM Research, 650 Harry Road, San Jose, California 95120, United States
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25
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Mahler A, Janesko BG, Moncho S, Brothers EN. When Hartree-Fock exchange admixture lowers DFT-predicted barrier heights: Natural bond orbital analyses and implications for catalysis. J Chem Phys 2018; 148:244106. [DOI: 10.1063/1.5032218] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Andrew Mahler
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76110, USA
| | - Benjamin G. Janesko
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76110, USA
| | - Salvador Moncho
- Chemistry Department, Texas A&M University at Qatar, Texas A&M Engineering Building, Education City, Doha, Qatar
| | - Edward N. Brothers
- Chemistry Department, Texas A&M University at Qatar, Texas A&M Engineering Building, Education City, Doha, Qatar
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26
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Fortenberry RC, Trabelsi T, Francisco JS. Hydrogen Sulfide as a Scavenger of Sulfur Atomic Cation. J Phys Chem A 2018; 122:4983-4987. [DOI: 10.1021/acs.jpca.8b02923] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry & Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, United States
- Department of Chemistry & Biochemistry, University of Mississippi, University, Mississippi 38677, United States
| | - Tarek Trabelsi
- Department of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
| | - Joseph S. Francisco
- Department of Chemistry, University of Nebraska—Lincoln, Lincoln, Nebraska 68588, United States
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27
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Morgan WJ, Matthews DA, Ringholm M, Agarwal J, Gong JZ, Ruud K, Allen WD, Stanton JF, Schaefer HF. Geometric Energy Derivatives at the Complete Basis Set Limit: Application to the Equilibrium Structure and Molecular Force Field of Formaldehyde. J Chem Theory Comput 2018; 14:1333-1350. [DOI: 10.1021/acs.jctc.7b01138] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- W. James Morgan
- Center for Computational Quantum Chemistry (CCQC), University of Georgia, Athens, Georgia 30602, United States
| | - Devin A. Matthews
- Institute for Computational Engineering and Sciences (ICES), University of Texas at Austin, Austin, Texas 78712, United States
| | - Magnus Ringholm
- Hylleraas Centre for Quantum Molecular Science, Department of Chemistry, University of Tromsø − The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Jay Agarwal
- Center for Computational Quantum Chemistry (CCQC), University of Georgia, Athens, Georgia 30602, United States
| | - Justin Z. Gong
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Kenneth Ruud
- Hylleraas Centre for Quantum Molecular Science, Department of Chemistry, University of Tromsø − The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Wesley D. Allen
- Center for Computational Quantum Chemistry (CCQC), University of Georgia, Athens, Georgia 30602, United States
| | - John F. Stanton
- Quantum Theory Project, University of Florida, Gainesville, Florida 32611, United States
| | - Henry F. Schaefer
- Center for Computational Quantum Chemistry (CCQC), University of Georgia, Athens, Georgia 30602, United States
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28
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Varandas AJC. Straightening the Hierarchical Staircase for Basis Set Extrapolations: A Low-Cost Approach to High-Accuracy Computational Chemistry. Annu Rev Phys Chem 2018; 69:177-203. [PMID: 29394151 DOI: 10.1146/annurev-physchem-050317-021148] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Because the one-electron basis set limit is difficult to reach in correlated post-Hartree-Fock ab initio calculations, the low-cost route of using methods that extrapolate to the estimated basis set limit attracts immediate interest. The situation is somewhat more satisfactory at the Hartree-Fock level because numerical calculation of the energy is often affordable at nearly converged basis set levels. Still, extrapolation schemes for the Hartree-Fock energy are addressed here, although the focus is on the more slowly convergent and computationally demanding correlation energy. Because they are frequently based on the gold-standard coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)], correlated calculations are often affordable only with the smallest basis sets, and hence single-level extrapolations from one raw energy could attain maximum usefulness. This possibility is examined. Whenever possible, this review uses raw data from second-order Møller-Plesset perturbation theory, as well as CCSD, CCSD(T), and multireference configuration interaction methods. Inescapably, the emphasis is on work done by the author's research group. Certain issues in need of further research or review are pinpointed.
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Affiliation(s)
- António J C Varandas
- Coimbra Chemistry Center and Department of Chemistry, University of Coimbra, Coimbra 3004-535, Portugal;
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29
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Fortenberry RC, Lee TJ, Layfield JP. Communication: The failure of correlation to describe carbon=carbon bonding in out-of-plane bends. J Chem Phys 2017; 147:221101. [DOI: 10.1063/1.5013026] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
| | - Timothy J. Lee
- MS 245-3 NASA Ames Research Center, Moffett Field, California 94035-1000, USA
| | - Joshua P. Layfield
- Department of Chemistry, University of St. Thomas, St. Paul, Minnesota 55105, USA
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30
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Tao Y, Zou W, Cremer D, Kraka E. Characterizing Chemical Similarity with Vibrational Spectroscopy: New Insights into the Substituent Effects in Monosubstituted Benzenes. J Phys Chem A 2017; 121:8086-8096. [PMID: 28960072 DOI: 10.1021/acs.jpca.7b08298] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A novel approach is presented to assess chemical similarity based the local vibrational mode analysis developed by Konkoli and Cremer. The local mode frequency shifts are introduced as similarity descriptors that are sensitive to any electronic structure change. In this work, 59 different monosubstituted benzenes are compared. For a subset of 43 compounds, for which experimental data was available, the ortho-/para- and meta-directing effect in electrophilic aromatic substitution reactions could be correctly reproduced, proving the robustness of the new similarity index. For the remaining 16 compounds, the directing effect was predicted. The new approach is broadly applicable to all compounds for which either experimental or calculated vibrational frequency information is available.
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Affiliation(s)
- Yunwen Tao
- Department of Chemistry, Southern Methodist University , 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Wenli Zou
- Institute of Modern Physics, Northwest University , Xi'an, Shaanxi 710069, People's Republic of China
| | - Dieter Cremer
- Department of Chemistry, Southern Methodist University , 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
| | - Elfi Kraka
- Department of Chemistry, Southern Methodist University , 3215 Daniel Avenue, Dallas, Texas 75275-0314, United States
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31
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Fortenberry RC, Lee TJ, Huang X. Towards completing the cyclopropenylidene cycle: rovibrational analysis of cyclic N 3+, CNN, HCNN +, and CNC . Phys Chem Chem Phys 2017; 19:22860-22869. [PMID: 28812071 DOI: 10.1039/c7cp04257d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The simple aromatic hydrocarbon, cyclopropenylidene (c-C3H2), is a known, naturally-occurring molecule. The question remains as to whether its isoelectronic, cyclic, fellow aromatics of c-N3+, c-CNN, HCNN+, and c-CNC- are as well. Each of these are exciting objects for observation of Titan, and the rotational constants and vibrational frequencies produced here will allow for remote sensing of Titan's atmosphere or other astrophysical or terrestrial sources. None of these four aromatic species are vibrationally strong absorbers/emitters, but the two ions, HCNN+ and c-CNC-, have dipole moments of greater than 3 D and 1 D, respectively, making them good targets for rotational spectroscopic observation. Each of these molecules is shown here to exhibit its own, unique vibrational properties, but the general trends put the vibrational behavior for corresponding fundamental modes within close ranges of one another, even producing nearly the same heavy atom, symmetric stretching frequencies for HCNN+ and c-C3H2 at 1600 cm-1. The c-N3+ cation is confirmed to be fairly unstable and has almost no intensity in its ν2 fundamental. Hence, it will likely remain difficult to characterize experimentally.
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Affiliation(s)
- Ryan C Fortenberry
- Georgia Southern University, Department of Chemistry and Biochemistry, Statesboro, GA 30460, USA.
| | - Timothy J Lee
- MS 245-3, NASA Ames Research Center, Moffett Field, CA 94035-1000, USA
| | - Xinchuan Huang
- SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043, USA
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32
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Fortenberry RC, Thackston R, Francisco JS, Lee TJ. Toward the laboratory identification of the not-so-simple NS2neutral and anion isomers. J Chem Phys 2017; 147:074303. [DOI: 10.1063/1.4985901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460-8064, USA
| | - Russell Thackston
- Department of Information Technology, Georgia Southern University, Statesboro, Georgia 30460-8150, USA
| | - Joseph S. Francisco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Timothy J. Lee
- MS 245-1, NASA Ames Research Center, Moffett Field, California 94035-1000, USA
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33
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Bassett MK, Fortenberry RC. Symmetry breaking and spectral considerations of the surprisingly floppy c-C 3H radical and the related dipole-bound excited state of c-C 3H . J Chem Phys 2017; 146:224303. [PMID: 29166048 DOI: 10.1063/1.4985095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The C3H radical is believed to be prevalent throughout the interstellar medium and may be involved in the formation of polycyclic aromatic hydrocarbons. C3H exists as both a linear and a cyclic isomer. The C2v cyclopropenylidenyl radical isomer was detected in the dark molecular cloud TMC-1, and the linear propenylidenyl radical isomer has been observed in various dark molecular clouds. Even though the c-C3H radical has been classified rotationally, the vibrational frequencies of this seemingly important interstellar molecule have never been directly observed. Established, highly accurate quartic force field methodologies are employed here to compute useful geometrical data, spectroscopic constants, and vibrational frequencies. The computed rotational constants are consistent with the experimental results. Consequently, the three a1 (ν1, ν2, and ν3) and one b1 (ν6) anharmonic vibrational frequencies at 3117.7 cm-1, 1564.3 cm-1, 1198.5 cm-1, and 826.7 cm-1, respectively, are reliable predictions for these, as of yet unseen, observables. Unfortunately, the two b2 fundamentals (ν4 and ν5) cannot be treated adequately in the current approach due to a flat and possible double-well potential described in detail herein. The dipole-bound excited state of the anion suffers from the same issues and may not even be bound. However, the trusted fundamental vibrational frequencies described for the neutral radical should not be affected by this deformity and are the first robustly produced for c-C3H. The insights gained here will also be applicable to other structures containing three-membered bare and exposed carbon rings that are surprisingly floppy in nature.
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Affiliation(s)
- Matthew K Bassett
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
| | - Ryan C Fortenberry
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
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Abstract
Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems.
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Affiliation(s)
| | - Kenneth M. Merz
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute of Cyber-Enabled Research, Michigan State University, East Lansing, Michigan 48824, United States
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35
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On the Detectability of the ${\tilde{{\boldsymbol{X}}}}^{2}{\boldsymbol{A}}^{\prime\prime} $ HSS, HSO, and HOS Radicals in the Interstellar Medium. ACTA ACUST UNITED AC 2017. [DOI: 10.3847/1538-4357/aa582d] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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36
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Murphy KV, Morgan WJ, Sun Z, Schaefer HF, Agarwal J. Thioformaldehyde S-Sulfide, Sulfur Analogue of the Criegee Intermediate: Structures, Energetics, and Rovibrational Analysis. J Phys Chem A 2017; 121:998-1006. [DOI: 10.1021/acs.jpca.6b12473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kevin V. Murphy
- Center for Computational
Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Whitney J. Morgan
- Center for Computational
Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Zhi Sun
- Center for Computational
Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Henry F. Schaefer
- Center for Computational
Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Jay Agarwal
- Center for Computational
Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
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37
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Semenikhin AS, Savchenkova AS, Chechet IV, Matveev SG, Liu Z, Frenklach M, Mebel AM. Rate constants for H abstraction from benzo(a)pyrene and chrysene: a theoretical study. Phys Chem Chem Phys 2017; 19:25401-25413. [DOI: 10.1039/c7cp05560a] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A theoretical study of H abstraction reactions from benzo[a]pyrene and chrysene shows differences in kinetic effectiveness of various radicals and a clear distinction between zigzag and armchair edges.
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Affiliation(s)
| | | | | | | | - Z. Liu
- Department of Mechanical Engineering
- University of California at Berkeley
- Berkeley
- USA
| | - M. Frenklach
- Department of Mechanical Engineering
- University of California at Berkeley
- Berkeley
- USA
| | - A. M. Mebel
- Samara National Research University
- Samara
- Russia
- Department of Chemistry and Biochemistry
- Florida International University
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38
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Filipek G, Fortenberry RC. Formation of Potential Interstellar Noble Gas Molecules in Gas and Adsorbed Phases. ACS OMEGA 2016; 1:765-772. [PMID: 31457160 PMCID: PMC6640802 DOI: 10.1021/acsomega.6b00249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 10/20/2016] [Indexed: 06/10/2023]
Abstract
The discovery of naturally occurring ArH+ in various regions of the interstellar medium has shown the need for more understanding of the reactions that lead to covalently bonded noble gas molecules. The test comes with trying to predict the formation of other small noble gas molecules. Many molecules have been observed in various interstellar environments, which possess the possibility of bonding with noble gases. This work explores how both argon and neon can form bonds to ligands made of these species through quantum chemical computations. Argon and neon are chosen as they are among the most abundant atoms in the universe but are more polarizable than the more common but smaller helium atom. Reactions leading to noble gas molecules are modeled in the gas phase as well as through the adsorbed phase by catalysis with a polycyclic aromatic hydrocarbon (PAH) surface. The adsorption energy of the neutral noble gas atoms to the surface increases as the size of the PAH also increases but this is still less than 10 kcal/mol. It is proposed and supported herein that an incoming molecule can bond with the noble gas atom adsorbed onto the PAH, form a stable structure, and allow the PAH to function as the leaving group. This work shows that the noble gas molecules ArCCH+, ArOH+, ArNH+, and NeCCH+ are not only stable minima on their respective potential energy surfaces but also can be formed in either the gas phase or through PAH adsorption with known or hypothesized interstellar molecules. Most notably, NeCCH+ does not appear to form in the gas phase but could be catalyzed on PAH surfaces. Hence, the interstellar detection of such molecules could also serve as a probe for the observation of interstellar PAHs.
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39
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Yost SR, Head-Gordon M. Size consistent formulations of the perturb-then-diagonalize Møller-Plesset perturbation theory correction to non-orthogonal configuration interaction. J Chem Phys 2016; 145:054105. [DOI: 10.1063/1.4959794] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Shane R. Yost
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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40
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Csontos J, Nagy B, Gyevi-Nagy L, Kállay M, Tasi G. Enthalpy Differences of the n-Pentane Conformers. J Chem Theory Comput 2016; 12:2679-88. [DOI: 10.1021/acs.jctc.6b00280] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- József Csontos
- MTA-BME
Lendület Quantum Chemistry Research Group, Department of Physical
Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box
91, Hungary
| | - Balázs Nagy
- MTA-BME
Lendület Quantum Chemistry Research Group, Department of Physical
Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box
91, Hungary
- Department
of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - László Gyevi-Nagy
- Department
of Applied and Environmental Chemistry, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
| | - Mihály Kállay
- MTA-BME
Lendület Quantum Chemistry Research Group, Department of Physical
Chemistry and Materials Science, Budapest University of Technology and Economics, H-1521 Budapest, P.O. Box
91, Hungary
| | - Gyula Tasi
- Department
of Applied and Environmental Chemistry, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
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41
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Potential interstellar noble gas molecules: ArOH + and NeOH + rovibrational analysis from quantum chemical quartic force fields. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molap.2015.12.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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42
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Fortenberry RC. Methylidyne-replaced boron nitride fullerenes and nanotubes: a wave function study. NEW J CHEM 2016. [DOI: 10.1039/c6nj01821a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Replacement of nitrogen atoms in boron nitride fullerenes and nanotubes with methylidyne groups stabilizes the structure and provides bonding points.
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43
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Affiliation(s)
- John F. Ouyang
- Department of Chemistry, National University of Singapore, 3 Science
Drive 3, Singapore 117543
| | - Ryan P. A. Bettens
- Department of Chemistry, National University of Singapore, 3 Science
Drive 3, Singapore 117543
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44
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Carrascal DJ, Ferrer J, Smith JC, Burke K. The Hubbard dimer: a density functional case study of a many-body problem. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:393001. [PMID: 26380948 DOI: 10.1088/0953-8984/27/39/393001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This review explains the relationship between density functional theory and strongly correlated models using the simplest possible example, the two-site Hubbard model. The relationship to traditional quantum chemistry is included. Even in this elementary example, where the exact ground-state energy and site occupations can be found analytically, there is much to be explained in terms of the underlying logic and aims of density functional theory. Although the usual solution is analytic, the density functional is given only implicitly. We overcome this difficulty using the Levy-Lieb construction to create a parametrization of the exact function with negligible errors. The symmetric case is most commonly studied, but we find a rich variation in behavior by including asymmetry, as strong correlation physics vies with charge-transfer effects. We explore the behavior of the gap and the many-body Green's function, demonstrating the 'failure' of the Kohn-Sham (KS) method to reproduce the fundamental gap. We perform benchmark calculations of the occupation and components of the KS potentials, the correlation kinetic energies, and the adiabatic connection. We test several approximate functionals (restricted and unrestricted Hartree-Fock and Bethe ansatz local density approximation) to show their successes and limitations. We also discuss and illustrate the concept of the derivative discontinuity. Useful appendices include analytic expressions for density functional energy components, several limits of the exact functional (weak- and strong-coupling, symmetric and asymmetric), various adiabatic connection results, proofs of exact conditions for this model, and the origin of the Hubbard model from a minimal basis model for stretched H2.
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Affiliation(s)
- D J Carrascal
- Department of Physics, Universidad de Oviedo, 33007 Oviedo, Spain. Nanomaterials and Nanotechnology Research Center, Oviedo, Spain
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45
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Affiliation(s)
- Ryan C. Fortenberry
- Georgia Southern University, Department of Chemistry, Statesboro, Georgia 30460, United States
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46
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Dos Santos LHR, Krawczuk A, Macchi P. Distributed Atomic Polarizabilities of Amino Acids and their Hydrogen-Bonded Aggregates. J Phys Chem A 2015; 119:3285-98. [DOI: 10.1021/acs.jpca.5b00069] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Leonardo H. R. Dos Santos
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, 3012 Bern, Switzerland
| | - Anna Krawczuk
- Faculty
of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland
| | - Piero Macchi
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, 3012 Bern, Switzerland
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47
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Thackston R, Fortenberry RC. The performance of low-cost commercial cloud computing as an alternative in computational chemistry. J Comput Chem 2015; 36:926-33. [PMID: 25753841 DOI: 10.1002/jcc.23882] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 12/16/2014] [Accepted: 02/08/2015] [Indexed: 01/15/2023]
Abstract
The growth of commercial cloud computing (CCC) as a viable means of computational infrastructure is largely unexplored for the purposes of quantum chemistry. In this work, the PSI4 suite of computational chemistry programs is installed on five different types of Amazon World Services CCC platforms. The performance for a set of electronically excited state single-point energies is compared between these CCC platforms and typical, "in-house" physical machines. Further considerations are made for the number of cores or virtual CPUs (vCPUs, for the CCC platforms), but no considerations are made for full parallelization of the program (even though parallelization of the BLAS library is implemented), complete high-performance computing cluster utilization, or steal time. Even with this most pessimistic view of the computations, CCC resources are shown to be more cost effective for significant numbers of typical quantum chemistry computations. Large numbers of large computations are still best utilized by more traditional means, but smaller-scale research may be more effectively undertaken through CCC services.
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Affiliation(s)
- Russell Thackston
- Department of Information Technology, Georgia Southern University, Statesboro, Georgia, 30460-8150
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48
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Morgan WJ, Fortenberry RC. Quartic force fields for excited electronic states: rovibronic reference data for the 1 (2)A' and 1 (2)A″ states of the isoformyl radical, HOC. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 135:965-972. [PMID: 25168234 DOI: 10.1016/j.saa.2014.07.082] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 07/23/2014] [Accepted: 07/28/2014] [Indexed: 06/03/2023]
Abstract
Quartic force fields (QFFs) have been shown to be an effective, accurate, and relatively compact means of computing rovibrational spectroscopic data for numerous molecules with numerous applications. However, excited states have been nearly excluded from the this approach since most accurate QFFs are based on the "gold standard" coupled cluster singles, doubles, and perturbative triples [CCSD(T)] method which is not readily extended to excited states. In this work, rovibronic spectroscopic data is provided for the isoformyl radical, a molecule of significance in combustion and astrochemistry, both through the traditional means of variational access to excited states with CCSD(T) and in the novel extension of QFFs routinely to treat electronically excited states through the standard coupled cluster excited state approach, equation of motion (EOM) CCSD. It is shown here that the new EOM-based QFF provides structural parameters and rotational constants that are quite close to those from a related CCSD(T)-based QFF for the 1 (2)A(″) excited state of HOC. The anharmonic vibrational frequency percent differences between the two QFFs are less than 0.4% for the O-H stretch, less than 1.9% for the C-O stretch, and around 3.0% for the bend. Even so, the pure excited state EOM-QFF anharmonic frequencies are still very good abinitio representations that may be applied to systems where electronically excited states are not variationally accessible. Additionally, rovibrational spectroscopic data is provided for the 1 (2)A(') ground state of HOC and for both the ground and excited state of DOC.
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Affiliation(s)
- W James Morgan
- Georgia Southern University, Department of Chemistry, Statesboro, GA 30460, USA
| | - Ryan C Fortenberry
- Georgia Southern University, Department of Chemistry, Statesboro, GA 30460, USA.
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49
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Craig NC, Demaison J, Groner P, Rudolph HD, Vogt N. Electron delocalization in polyenes: a semiexperimental equilibrium structure for (3E)-1,3,5-hexatriene and theoretical structures for (3Z,5Z)-, (3E,5E)-, and (3E,5Z)-1,3,5,7-octatetraene. J Phys Chem A 2015; 119:195-204. [PMID: 25465856 DOI: 10.1021/jp510237h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Electronic structure theory reveals that π-electron delocalization increases with the chain length in polyenes. To analyze quantitatively this effect a semiexperimental equilibrium structure has been determined for trans-hexatriene by the mixed estimation method. For this fit rotational constants for a number of carbon and hydrogen isotopologues as well as a high-level ab initio structure have been used. The accuracy is 0.001 Å for bond lengths and 0.1° for bond angles. For the three isomers of octatetraene, high-level ab initio calculations have given a comparably accurate structure. These structures have been used in comparison with the structure of s-trans-butadiene to show that "C═C" bonds increase in length and "C-C" bonds decrease in length as the polyene chain lengthens. These structural effects of π-electron delocalization increase toward the center of polyenes. Most likely, π-π conjugation in the molecules studied plays a large part in their planarity that, in turn, forces the hydrogen atoms of cis fragments in bay regions to be in a close contact. Their distance is indeed shorter than the sum of their van der Waals radii, and they seem to participate in a six-membered ring.
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Affiliation(s)
- Norman C Craig
- Department of Chemistry and Biochemistry, Oberlin College , Oberlin, Ohio 44074, United States
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50
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Bakowies D. Simplified Wave Function Models in Thermochemical Protocols Based on Bond Separation Reactions. J Phys Chem A 2014; 118:11811-27. [DOI: 10.1021/jp510249v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dirk Bakowies
- Laboratory of Physical Chemistry, ETH Zürich, CH 8093 Zürich, Switzerland
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