In this series of studies, we systematically apply the analytical energy gradients of the direct symmetry-adapted cluster–configuration interaction singles and doubles nonvariational method to calculate the equilibrium geometries and vibrational frequencies of excited and ionized states of molecules. The harmonic vibrational frequencies were calculated using the second derivatives numerically computed from the analytical first derivatives and the anharmonicity was evaluated from the three-dimensional potential energy surfaces around the local minima. In this paper, the method is applied to the low-lying valence singlet and triplet excited states of HAX-type molecules, HCF, HCCl, HSiF, HSiCl, HNO, HPO, and their deuterium isotopomers. The vibrational level emission spectra of HSiF and DSiF and absorption spectra of HSiCl and DSiCl were also simulated within the Franck–Condon approximation and agree well with the experimental spectra. The results show that the present method is useful and reliable for calculating these quantities and spectra. The change in geometry in the excited states was qualitatively interpreted in the light of the electrostatic force theory. The effect of perturbation selection with the localized molecular orbitals on the geometrical parameters and harmonic vibrational frequencies is also discussed.
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28 July 2011
Research Article|
July 29 2011
Excited-state geometries and vibrational frequencies studied using the analytical energy gradients of the direct symmetry-adapted cluster–configuration interaction method. I. HAX-type molecules
Masahiro Ehara;
Masahiro Ehara
a)
1
Institute for Molecular Science
, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
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Fumito Oyagi;
Fumito Oyagi
2Department of Synthetic Chemistry and Biological Chemistry,
Kyoto University
, Katsura, Kyoto 615-8510, Japan
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Yoko Abe;
Yoko Abe
2Department of Synthetic Chemistry and Biological Chemistry,
Kyoto University
, Katsura, Kyoto 615-8510, Japan
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Ryoichi Fukuda;
Ryoichi Fukuda
1
Institute for Molecular Science
, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan
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Hiroshi Nakatsuji
Hiroshi Nakatsuji
a)
2Department of Synthetic Chemistry and Biological Chemistry,
Kyoto University
, Katsura, Kyoto 615-8510, Japan
3
Quantum Chemistry Research Institute
, Goryo Oohara 1-36, Nishikyo-ku, Kyoto 615-8245, Japan
4
JST, CREST
, Sanboncho-5, Chiyoda-ku, Tokyo 102-0075, Japan
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a)
Authors to whom correspondence should be addressed. Electronic addresses: ehara@ims.ac.jp and h.nakatsuji@qcri.or.jp.
J. Chem. Phys. 135, 044316 (2011)
Article history
Received:
March 30 2011
Accepted:
July 06 2011
Citation
Masahiro Ehara, Fumito Oyagi, Yoko Abe, Ryoichi Fukuda, Hiroshi Nakatsuji; Excited-state geometries and vibrational frequencies studied using the analytical energy gradients of the direct symmetry-adapted cluster–configuration interaction method. I. HAX-type molecules. J. Chem. Phys. 28 July 2011; 135 (4): 044316. https://doi.org/10.1063/1.3617233
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