Spin-orbit Coupling and Intersystem Crossing in 4H-Pyran-4-thione: CASSCF//TD-B3LYP Study

• 来源期刊: 中国化学(英文版)
• 年，卷（期）: 2007,（10）
• 页码范围: 1461-1466
• 页数: 6页
• 语种: 英文

摘要

The intersystem crossing channels of gaseous 4H-pyran-4-thione were investigated using the CASSCF//TD-B3LYP methods and group theory. Using the effective one-electron spin-orbit Hamiltonian, the strengths of spin-orbit coupling were estimated, which plays an essential role in the spin transitions between different spin states. Calculated results show that phosphorescence and non-radiative decay via intersystem crossing to the S0 state are concurrent processes occurring at the T1 state. A rapid depletion of the S1 state via intersystem crossing to the T1 state can be mediated by the T2 state, if spin relaxation is fast within the triplet levels. Our calculated results are in close agreement with experimental observations.