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Nakatsuji H, Nakashima H. Potential curves of the lower nine states of Li2 molecule: Accurate calculations with the free complement theory and the comparisons with the SAC/SAC-CI results. J Chem Phys 2022; 157:094109. [DOI: 10.1063/5.0101315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The free-complement (FC) theory proposed for solving the Schrödinger equation of atoms and molecules highly accurately was applied to the calculations of the potential curves of the lower nine states of the Li2 molecule. The results were compared with the accurate experimental Rydberg-Klein-Rees (RKR) potential curves available. They overlap completely with each other without any shift everywhere for all the states of Li2. At all the calculated points on the seven potential curves ranging between -14.83 ~ -15.00 hartree, the average difference was only 0.0583 kcal/mol and the maximum difference was only +0.165 kcal/mol. For the vertical excitation energies from the ground state curve to the seven excited states, the differences between theory and experiment were 0.000645 eV in average and their maximum difference was -0.00720 eV. The potential properties calculated with the FC theory also agreed well with the experimental values. These results show a high potentiality of the FC theory as a highly predictive quantum chemistry theory. For comparison, as an example of the Hartree-Fock based theory popular in modern quantum chemistry, we adopted the SAC-CI theory using a highly flexible basis set. While the FC theory gave the absolute agreements with experiments, the SAC-CI potential curves compare reasonably well with experiments only after shifting-down of the SAC-CI curves by 5.727 kcal/mol. The differences of the excitation energies between SAC-CI and experiments were 0.00428 eV in average and the maximum difference was +0.10967 eV. The SAC-CI results reported in 1985 were less accurate but still reasonable.
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Affiliation(s)
- Hiroshi Nakatsuji
- Quantum Chemistry Research Institute, Quantum Chemistry Research Institute, Japan
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Egidi F, Sun S, Goings JJ, Scalmani G, Frisch MJ, Li X. Two-Component Noncollinear Time-Dependent Spin Density Functional Theory for Excited State Calculations. J Chem Theory Comput 2017; 13:2591-2603. [DOI: 10.1021/acs.jctc.7b00104] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Franco Egidi
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Shichao Sun
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Joshua J. Goings
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Giovanni Scalmani
- Gaussian Inc., 340 Quinnipiac
Street, Building 40, Wallingford, Connecticut 06492, United States
| | - Michael J. Frisch
- Gaussian Inc., 340 Quinnipiac
Street, Building 40, Wallingford, Connecticut 06492, United States
| | - Xiaosong Li
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
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Musiał M, Kucharski SA. First Principle Calculations of the Potential Energy Curves for Electronic States of the Lithium Dimer. J Chem Theory Comput 2014; 10:1200-11. [DOI: 10.1021/ct401076e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Monika Musiał
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland
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Zhao J, Zeng H, Zhu Z. A theoretical study of the accurate analytic potential energy curve and spectroscopic properties for AlF (X1Σ+). COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.10.013] [Citation(s) in RCA: 3] [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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