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Software for the frontiers of quantum chemistry: An overview of developments in the Q-Chem 5 package. J Chem Phys 2021; 155:084801. [PMID: 34470363 PMCID: PMC9984241 DOI: 10.1063/5.0055522] [Citation(s) in RCA: 412] [Impact Index Per Article: 137.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange-correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear-electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an "open teamware" model and an increasingly modular design.
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Dehydrative cyclocondensation mechanisms of hydrogen thioperoxide and of alkanesulfenic acids. J Phys Chem A 2012; 116:8031-9. [PMID: 22724673 DOI: 10.1021/jp3024827] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Structural features of hydrogen thioperoxide (oxadisulfane, H-S-O-H) and of alkanesulfenic acids (R-S-O-H; R = CH3, CH2CH3, CH2CH2CH3, CH(CH3)2, C(CH3)3, CF3, CCl3) and the mechanisms of their dehydrative cyclocondensation to the respective sulfinothioic acid (H-(S═O)-S-H) and alkyl alkanethiosulfinates (R-(S═O)-S-R) have been studied using coupled cluster theory with single and double and perturbative triple excitations [CCSD(T)] and quadratic configuration interaction with single and double and perturbative triple excitations [QCISD(T)] with the cc-pVDZ basis set and also using second-order Møller-Plesset perturbation theory (MP2) and the hybrid density functionals B3LYP, B3PW91, and PBE1PBE with the 6-311+G(d,p) basis set. The concerted cyclodehydration mechanisms include cyclic five-center transition states with relatively long distance sulfur-sulfur bonding interactions. Attractive and repulsive nonbonding interactions are predicted in the sulfenic acids, transition states, and thiosulfinates. In the alkyl alkanethiosulfinates attractive cyclic C-H----O═S nonbonding interactions are predicted. CCSD(T) and QCISD(T) predict similar values for the relative energies and CCSD(T) predicts the barrier to the cyclocondensation of H-S-O-H to sulfinothioic acid (H-(S═O)-S-H) to be 41.8 kcal/mol, and barriers in the range of 37.5 to 39.6 kcal/mol are predicted for the condensation of alkanesulfenic acids to alkyl alkanethiosulfinates.
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The Total Synthesis of Roquefortine C and a Rationale for the Thermodynamic Stability of Isoroquefortine C over Roquefortine C. J Am Chem Soc 2008; 130:6281-7. [DOI: 10.1021/ja800067q] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Advances in theory and algorithms for electronic structure calculations must be incorporated into program packages to enable them to become routinely used by the broader chemical community. This work reviews advances made over the past five years or so that constitute the major improvements contained in a new release of the Q-Chem quantum chemistry package, together with illustrative timings and applications. Specific developments discussed include fast methods for density functional theory calculations, linear scaling evaluation of energies, NMR chemical shifts and electric properties, fast auxiliary basis function methods for correlated energies and gradients, equation-of-motion coupled cluster methods for ground and excited states, geminal wavefunctions, embedding methods and techniques for exploring potential energy surfaces.
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An evaluation of the performance of diffuse function-augmented basis sets for second row elements, Na-Cl. J Comput Chem 2004. [DOI: 10.1002/jcc.540080807] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hyperconjugation and homohyperconjugation in the 1-adamantyl cation. Qualitative models for .gamma.-deuterium isotope effects. J Am Chem Soc 2002. [DOI: 10.1021/ja00515a002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Heat of formation of hydrogen isocyanide by ion cyclotron double resonance spectroscopy. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100392a006] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Thermochemistry of Group IVA isobutene analogs by pulsed ion cyclotron double resonance spectroscopy. J Am Chem Soc 2002. [DOI: 10.1021/ja00380a003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Stereoelectronic effects in the gas-phase. 2. Negative ion reactions of 1,3-dithianes and 1,3-dithiane 1-oxides. J Am Chem Soc 2002. [DOI: 10.1021/ja00201a015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Direct calculation of equilibrium constants for isotopic exchange reactions by ab initio molecular orbital theory. J Am Chem Soc 2002. [DOI: 10.1021/ja00529a090] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Selection of configurations for parameterization of two-body interaction potentials. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100364a076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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An ab initio molecular orbital study of the rearrangement of .alpha.-disulfoxide to thiosulfonate. J Am Chem Soc 2002. [DOI: 10.1021/ja00369a001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Correlation of STO-3G calculated substituent effects on the proton affinity of benzene with .sigma.+ parameters. J Am Chem Soc 2002. [DOI: 10.1021/ja00417a045] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Conformation, configuration, and reactivity of thiosulfonium ions derived from 1,2-dithianes and 1,2-dithiolanes. Stereoelectronic effects. J Am Chem Soc 2002. [DOI: 10.1021/ja00295a044] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Modeling chemical reactivity. 1. Regioselectivity of Diels-Alder cycloadditions of electron-rich dienes with electron-deficient dienophiles. J Am Chem Soc 2002. [DOI: 10.1021/ja00283a038] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Molecular orbital theory of the electronic structure of organic compounds. XVII. Internal rotation in 1,2-disubstituted ethanes. J Am Chem Soc 2002. [DOI: 10.1021/ja00784a008] [Citation(s) in RCA: 217] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Self-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elements. J Am Chem Soc 2002. [DOI: 10.1021/ja00523a008] [Citation(s) in RCA: 3406] [Impact Index Per Article: 154.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Molecular orbital theory of the electronic structure of organic compounds. XXVI. Geometries, energies and polarities of C4 hydrocarbons. J Am Chem Soc 2002. [DOI: 10.1021/ja00857a002] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Modeling chemical reactivity. 7. The effect of a change in rate-limiting step on the stereoselectivity of electrophilic addition to allylic alcohols and related chiral alkenes. J Am Chem Soc 2002. [DOI: 10.1021/ja00237a006] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Self-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elements. J Am Chem Soc 2002. [DOI: 10.1021/ja00374a017] [Citation(s) in RCA: 1424] [Impact Index Per Article: 64.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gas-phase basicities of substituted anilines. Inferences about the role of solvent in dictating site of protonation. J Am Chem Soc 2002. [DOI: 10.1021/ja00456a009] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Degenerate rearrangement in homocyclopropenyl cation. Violation of orbital symmetry control for a sigmatropic migration. J Am Chem Soc 2002. [DOI: 10.1021/ja00818a046] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Atomic fits to electron densities in polyatomic molecules. Correlation of atom size and charge. J Am Chem Soc 2002. [DOI: 10.1021/ja00349a073] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Molecular orbital theory of the electronic structure of organic compounds. XVIII. Conformations and stabilities of trisubstituted methanes. J Am Chem Soc 2002. [DOI: 10.1021/ja00784a009] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Determination of the heats of formation of the isomeric xylylenes by ion cyclotron double-resonance spectroscopy. J Am Chem Soc 2002. [DOI: 10.1021/ja00411a007] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Face selectivity in Diels-Alder reactions of chiral dienes containing allylic substituents. J Am Chem Soc 2002. [DOI: 10.1021/ja00222a022] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Molecular orbital theory of the electronic structure of organic compounds. III. Ab initio studies of charge distribution using a minimal Slater-type basis. J Am Chem Soc 2002. [DOI: 10.1021/ja00711a001] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Heats of formation of gaseous free radicals via ion cyclotron double resonance spectroscopy. J Am Chem Soc 2002. [DOI: 10.1021/ja00530a005] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Molecular orbital theory of the electronic structure of organic compounds. V. Molecular theory of bond separation. J Am Chem Soc 2002. [DOI: 10.1021/ja00719a006] [Citation(s) in RCA: 760] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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