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Majumder R, Sokolov AY. Consistent Second-Order Treatment of Spin-Orbit Coupling and Dynamic Correlation in Quasidegenerate N-Electron Valence Perturbation Theory. J Chem Theory Comput 2024; 20:4676-4688. [PMID: 38795071 DOI: 10.1021/acs.jctc.4c00458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2024]
Abstract
We present a formulation and implementation of second-order quasidegenerate N-electron valence perturbation theory (QDNEVPT2) that provides a balanced and accurate description of spin-orbit coupling and dynamic correlation effects in multiconfigurational electronic states. In our approach, the energies and wave functions of electronic states are computed by treating electron repulsion and spin-orbit coupling operators as equal perturbations to the nonrelativistic complete active-space wave functions, and their contributions are incorporated fully up to the second order. The spin-orbit effects are described using the Breit-Pauli (BP) or exact two-component Douglas-Kroll-Hess (DKH) Hamiltonians within spin-orbit mean-field approximation. The resulting second-order methods (BP2- and DKH2-QDNEVPT2) are capable of treating spin-orbit coupling effects in nearly degenerate electronic states by diagonalizing an effective Hamiltonian expanded in a compact non-relativistic basis. For a variety of atoms and small molecules across the entire periodic table, we demonstrate that DKH2-QDNEVPT2 is competitive in accuracy with variational two-component relativistic theories. BP2-QDNEVPT2 shows high accuracy for the second- and third-period elements, but its performance deteriorates for heavier atoms and molecules. We also consider the first-order spin-orbit QDNEVPT2 approximations (BP1- and DKH1-QDNEVPT2), among which DKH1-QDNEVPT2 is reliable but less accurate than DKH2-QDNEVPT2. Both DKH1- and DKH2-QDNEVPT2 hold promise as efficient and accurate electronic structure methods for treating electron correlation and spin-orbit coupling in a variety of applications.
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Affiliation(s)
- Rajat Majumder
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Alexander Yu Sokolov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
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Cheng L, Wang F, Stanton JF, Gauss J. Perturbative treatment of spin-orbit-coupling within spin-free exact two-component theory using equation-of-motion coupled-cluster methods. J Chem Phys 2018; 148:044108. [DOI: 10.1063/1.5012041] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Fan Wang
- Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology, Ministry of Education, Sichuan University, Chengdu, China
| | - John F. Stanton
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
| | - Jürgen Gauss
- Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz, Germany
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Liu J, Shen Y, Asthana A, Cheng L. Two-component relativistic coupled-cluster methods using mean-field spin-orbit integrals. J Chem Phys 2018; 148:034106. [DOI: 10.1063/1.5009177] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Junzi Liu
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yue Shen
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Ayush Asthana
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA
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Zavitsas AA. Factors affecting the relation between stretching frequencies and bond lengths. Diatomic and polyatomic species without adjustable fitting parameters. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 151:553-565. [PMID: 26162344 DOI: 10.1016/j.saa.2015.07.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 06/04/2023]
Abstract
In 76 sets of similar type bonds in species A2, AB, AB2, AB3, and AB4 the stretching frequency, ν, is related to the bond length, r, by ν=a/(rμ(1/2))-b, where μ is the reduced mass. The sets treated include all ground states for which spectroscopic date were found for stable molecules, free radicals, carbenes and other species with unsatisfied valences, both ionic and covalent. The linear correlation coefficients of each set are always greater than 0.998. The slopes a and intercepts b are defined by the data of each set and vary widely. They become congruent, but not exactly identical, when a is multiplied by the square root of the mean value of the number of electrons in the valence shell of the two bonded atoms, the electrons that become joined in the molecular orbitals formed upon bonding. No adjustable parameters are used. The number of bonds treated, over 300, is not as important as the fact that all species found were treated. The aim is not to add yet another parametric correlation to the many extant, but to better understand the relation between these two fundamental properties of chemical bonds.
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Affiliation(s)
- Andreas A Zavitsas
- Department of Chemistry and Biochemistry, Long Island University, University Plaza, Brooklyn, NY 11201, USA.
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Li S, Zheng R, Chen SJ, Zhu DS, Fan QC. Theoretical study on the ground electronic state of FO(+) and FO(-). SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 133:735-740. [PMID: 24996216 DOI: 10.1016/j.saa.2014.06.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 05/23/2014] [Accepted: 06/08/2014] [Indexed: 06/03/2023]
Abstract
The equilibrium structures of the ground electronic states for molecular ions FO(+) and FO(-) have been calculated by using the multi-reference configuration interaction method in combination with the augmented correlation-consistent basis sets up through sextuple zeta quality. The equilibrium parameters, potential energy curves and spectroscopic constants are derived for both species. The extrapolation schemes are adopted to estimate the complete basis set limit. The corrections of core-valence correlation and relativistic effect are included to improve the accuracy of the calculations. The vibrational energy levels as well as rotational and centrifugal distortion constants of the ground electronic states for both systems are obtained by solving the radial Schrödinger equation of nuclear motion. The computations on neutral FO radical are also carried out to investigate the ionization potentials and the electron affinities.
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Affiliation(s)
- Song Li
- College of Physical Science and Technology, Yangtze University, Jingzhou 434023, China.
| | - Rui Zheng
- School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou 450011, China
| | - Shan-Jun Chen
- College of Physical Science and Technology, Yangtze University, Jingzhou 434023, China
| | - De-Sheng Zhu
- College of Physical Science and Technology, Yangtze University, Jingzhou 434023, China
| | - Qun-Chao Fan
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu 610039, China
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Sokolov AY, Schaefer HF. Orbital-optimized density cumulant functional theory. J Chem Phys 2014; 139:204110. [PMID: 24289347 DOI: 10.1063/1.4833138] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In density cumulant functional theory (DCFT) the electronic energy is evaluated from the one-particle density matrix and two-particle density cumulant, circumventing the computation of the wavefunction. To achieve this, the one-particle density matrix is decomposed exactly into the mean-field (idempotent) and correlation components. While the latter can be entirely derived from the density cumulant, the former must be obtained by choosing a specific set of orbitals. In the original DCFT formulation [W. Kutzelnigg, J. Chem. Phys. 125, 171101 (2006)] the orbitals were determined by diagonalizing the effective Fock operator, which introduces partial orbital relaxation. Here we present a new orbital-optimized formulation of DCFT where the energy is variationally minimized with respect to orbital rotations. This introduces important energy contributions and significantly improves the description of the dynamic correlation. In addition, it greatly simplifies the computation of analytic gradients, for which expressions are also presented. We offer a perturbative analysis of the new orbital stationarity conditions and benchmark their performance for a variety of chemical systems.
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Affiliation(s)
- Alexander Yu Sokolov
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, USA
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Woon DE, Dunning TH. A comparison between polar covalent bonding and hypervalent recoupled pair bonding in diatomic chalcogen halide species {O,S,Se} × {F,Cl,Br}. Mol Phys 2010. [DOI: 10.1080/00268970802712431] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sikkema J, Visscher L, Saue T, Iliaš M. The molecular mean-field approach for correlated relativistic calculations. J Chem Phys 2009; 131:124116. [DOI: 10.1063/1.3239505] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Karton A, Parthiban S, Martin JML. Post-CCSD(T) ab Initio Thermochemistry of Halogen Oxides and Related Hydrides XOX, XOOX, HOX, XOn, and HXOn (X = F, Cl), and Evaluation of DFT Methods for These Systems. J Phys Chem A 2009; 113:4802-16. [DOI: 10.1021/jp8087435] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Amir Karton
- Department of Organic Chemistry, Weizmann Institute of Science, IL-76100 Rehovot, Israel
| | - Srinivasan Parthiban
- Department of Organic Chemistry, Weizmann Institute of Science, IL-76100 Rehovot, Israel
| | - Jan M. L. Martin
- Department of Organic Chemistry, Weizmann Institute of Science, IL-76100 Rehovot, Israel
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Harding ME, Vázquez J, Ruscic B, Wilson AK, Gauss J, Stanton JF. High-accuracy extrapolated ab initio thermochemistry. III. Additional improvements and overview. J Chem Phys 2008; 128:114111. [PMID: 18361558 DOI: 10.1063/1.2835612] [Citation(s) in RCA: 327] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Effects of increased basis-set size as well as a correlated treatment of the diagonal Born-Oppenheimer approximation are studied within the context of the high-accuracy extrapolated ab initio thermochemistry (HEAT) theoretical model chemistry. It is found that the addition of these ostensible improvements does little to increase the overall accuracy of HEAT for the determination of molecular atomization energies. Fortuitous cancellation of high-level effects is shown to give the overall HEAT strategy an accuracy that is, in fact, higher than most of its individual components. In addition, the issue of core-valence electron correlation separation is explored; it is found that approximate additive treatments of the two effects have limitations that are significant in the realm of <1 kJ mol(-1) theoretical thermochemistry.
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Affiliation(s)
- Michael E Harding
- Institut für Physikalische Chemie, Universität Mainz, Mainz, Germany
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Transition state spectroscopy of open shell systems: Angle-resolved photodetachment spectra for the adiabatic singlet states of OHF. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2007.01.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ramachandran B. Scaling Dynamical Correlation Energy from Density Functional Theory Correlation Functionals. J Phys Chem A 2005; 110:396-403. [PMID: 16405310 DOI: 10.1021/jp050584x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The scaling of dynamical correlation energy in molecules obtained by the correlation functionals of density functional theory (DFT) is examined. The approach taken is very similar to the scaled external correlation method of Brown and Truhlar but is based on the observation that DFT correlation functionals, especially the LYP, appear to represent the dynamical portion of the correlation energy in molecules. We examine whether higher accuracy in atomization energies can be gained by scaling without significant deterioration of the structural and spectroscopic properties of the molecules using four DFT functionals (BLYP, OLYP, B3LYP, and O3LYP) on 19 molecules including the six molecule AE6 database, the latter being representative of a much larger, 109 molecule training set. We show that, with molecule specific scale factors, nearly perfect agreement with experiment can be achieved in atomization energies without increasing the average errors in other molecular properties relative to the DFT calculation. We further show that it is possible to find optimal scale factors which reduce the mean unsigned error per bond to levels comparable to those of some multilevel multicoefficient methods.
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Affiliation(s)
- B Ramachandran
- Chemistry, College of Engineering and Science, Louisiana Tech University, Ruston, Louisiana 71272, USA.
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Gómez-Carrasco S, González-Snchez L, Aguado A, Roncero O, Alvariño JM, Hernández ML, Paniagua M. Direct versus resonances mediated F+OH collisions on a new 3A″ potential energy surface. J Chem Phys 2004; 121:4605-18. [PMID: 15332891 DOI: 10.1063/1.1780168] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A theoretical study of the F(2P) + OH(2Pi) --> HF(1Sigma+) + O(3P) reactive collisions is carried out on a new global potential energy surface (PES) of the ground 3A" adiabatic electronic state. The ab initio calculations are based on multireference configuration interaction calculations, using the aug-cc-pVTZ extended basis sets of Dunning et al. A functional representation of the PES shows no nominal barrier to reaction, contrary to previous results by others. Wave packet and quasiclassical trajectory calculations have been performed for this PES to study the F + OH(v = 0,j) reactive collision. The comparison was performed at fixed and constant values of the total angular momentum from 0 to 110 and relative translational energy up to 0.8 eV. The reaction presents a dynamical barrier, essentially due to the zero-point energy for the bending vibration near the saddle point. This determines two different reaction mechanisms. At energies higher than approximately 0.125 eV the reaction is direct, while below that value it is indirect and mediated by heavy-light-heavy resonances. Such resonances, also found in the simulations of the photodetachment spectrum of the triatomic anion, manifest themselves in the quasiclassical simulations, too, where they are associated to periodic orbits.
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Affiliation(s)
- Susana Gómez-Carrasco
- Departamento de Quimica Fisica, Facultad de Quimica, Universidad de Salamanca, 37008 Salamanca, Spain
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Ervin KM, Anusiewicz I, Skurski P, Simons J, Lineberger WC. The Only Stable State of O2-Is the X2ΠgGround State and It (Still!) Has an Adiabatic Electron Detachment Energy of 0.45 eV. J Phys Chem A 2003. [DOI: 10.1021/jp0357323] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ramachandran B, Vegesna NS, Peterson KA. Effects of Electron Correlation and Scalar Relativistic Corrections on the Thermochemical and Spectroscopic Properties of HOF. J Phys Chem A 2003. [DOI: 10.1021/jp035266h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- B. Ramachandran
- Chemistry, College of Engineering and Science, Louisiana Tech University, Ruston, Louisiana 71272, and Department of Chemistry, Washington State University, Pullman, Washington 99164-4630
| | - Naga Srivani Vegesna
- Chemistry, College of Engineering and Science, Louisiana Tech University, Ruston, Louisiana 71272, and Department of Chemistry, Washington State University, Pullman, Washington 99164-4630
| | - Kirk A. Peterson
- Chemistry, College of Engineering and Science, Louisiana Tech University, Ruston, Louisiana 71272, and Department of Chemistry, Washington State University, Pullman, Washington 99164-4630
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Klopper W, Noga J. Accurate quantum-chemical prediction of enthalpies of formation of small molecules in the gas phase. Chemphyschem 2003; 4:32-48. [PMID: 12596464 DOI: 10.1002/cphc.200390006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The coupled-cluster approach, including single and double excitations and perturbative corrections for triple excitations, is capable of predicting molecular electronic energies and enthalpies of formation of small molecules in the gas phase with very high accuracy (specifically, with error bars less than 5 kJmol-1), provided that the electronic wavefunction is dominated by the Hartree-Fock configuration. This capability is illustrated by calculations on molecules containing O-H and O-F bonds, namely OH, FO, H2O, HOF, and F2O. To achieve this very high accuracy, it is imperative to account for electron-correlation effects in a quantitative manner, either by using explicitly correlated two-particle basis functions (R12 functions) or by extrapolating to the limit of a complete basis. Besides taking into account harmonic zero-point vibrational energies, it is also necessary to account for anharmonic corrections to the zero-point vibrational energies, to include the core orbitals into the coupled-cluster calculations, and to account for spin-orbit corrections and scalar relativistic effects. These additional corrections constitute small but significant contributions in the range of 1-4 kJmol-1 to the enthalpies of formation of the aforementioned molecules. The highly accurate coupled-cluster results, obtained by employing R12 functions and by including various corrections, are compared with standard Kohn-Sham density-functional calculations as well as with the Gaussian-2 and complete-basis-set model chemistries.
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Affiliation(s)
- Wim Klopper
- Universität Karlsruhe (TH) Institut für Physikalische Chemie Lehrstuhl für Theoretische Chemie Kaiserstrasse 12, 76128 Karlsruhe, Germany.
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