CASSCF/CASPT2 calculation of the low-lying electronic states of the CH3Se neutral radical and its cation.
Electronic states of the CH(3)Se and its cation CH(3)Se(+) have been studied using the complete active space self-consistent field (CASSCF) and multiconfiguration second-order perturbation theory (CASPT2) methods in conjunction with the ANO-RCC(TZP) basis set. To investigate the Jahn-Teller effect on the CH(3)Se radical, C(s) symmetry was used for CH(3)Se in calculations. The results show that the Jahn-Teller effect is very small (69 cm(-1)) and the 1(2)A' state is slightly more stable than the 1(2)A'' state (8 cm(-1)). The CH(3)Se has been found to have a 1(2)A' ground state with a C-Se bond distance of 1.975 A. The computed C-Se stretching nu(6)(a') frequency is 554.1 cm(-1), which is in good agreement with the experimental values of 600 +/- 60 cm(-1). The calculations for CH(3)Se at 3.621 and 5.307 eV are attributed to 1(2)A' --> 2(2)A'(1(2)A(1)) and 1(2)A' --> 2(2)A'', respectively. The vertical and adiabatic ionization energies were obtained to compare with the PES data.
Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China.
Ming-Xing
MX
Song
Zeng-Xia
ZX
Zhao
Fu-Quan
FQ
Bai
Yue-Jie
YJ
Liu
Hong-Xing
HX
Zhang
Chia-Chung
CC
Sun
D002412:Cations / Q000737:chemistry; D004583:Electrons; D016566:Organoselenium Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D011789:Quantum Theory; D013455:Sulfur / Q000737:chemistry; D013816:Thermodynamics; D014732:Vibration
D002412:Cations; D016566:Organoselenium Compounds; D013455:Sulfur; D010100:Oxygen