The strong temperature dependence of T1→ S0 intersystem crossing (ISC) and the energy dependence of T1→ S0 under collision-free conditions is semiquantitatively discussed on the basis of a model in which consideration is given to low frequency modes that undergo a large increase in frequency in going from T1 to S0. It is shown that such modes play a key role in the strong temperature or energy dependence. The increase in ISC rate by methylation, which has been reported for benzene and diazabenzenes in solid matrices, is explained by the assumption that the frequencies of the vibronic coupling modes are reduced more in T1 than in S0 because of the reduction in the T2-T1 energy gap by methylation.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry