Effect of vibronically induced spin-orbit coupling of electronic ππ* states on nonradiative intersystem crossing: Naphthalene

The effect of (I) S (1)((1) B (2u) ) -> T (1)((3) B (1u) ) and (II) S (1) -> T (2) ((3) B (3g) ) -> T (1) transitions in naphthalene on the rate constant K (ST) (s) of the S (1) -> T (1) nonradiative transitions to all triplet sublevels s = z, y, x of the T (1) state has been investigated in the approximation of vibronically induced spin-orbit couplings, taking into account all out-of-plane vibrational modes. The shapes of the vibrational modes that are most active in these transitions are determined. The calculated values K (ST) = (0.33-0.75) x 10(7) s(-1), obtained with allowance for the I and I + II transitions, are consistent with the experimental values (K (ST))(exp) found by different researchers. It is established in all calculation versions that K (ST) > K (ST) (z) > k(ST) (x) . This relation is in qualitative agreement with the known magnetooptical data.