GENERALIZED GOLDEN-RULE APPROACH TO THE H-TRANSFER PROBLEM .2. APPLICATION TO A PHOTOCHEMICAL-REACTION

The golden rule approach generalized for arbitrary values of the electronic coupling integral, as reported earlier, is applied to interpret the kinetic data and discuss the driving forces of the fast photochemical H- and D-transfer in acridine-doped fluorene crystal. The excited-state proton transfer (ESPT) is treated as multidimensional tunneling. Both the stretching and bending vibrations of the transferred H atom and the lattice phonons which affect the tunneling distance are taken into account. The relatively large value of the electronic coupling J between the initial and final state corresponding to the fluorene-triplet acridine, and triplet acridinyl-fluorenyl radical pair complex, respectively, is found to be the main reason for the unusually rapid reaction. This conclusion is supported by a direct estimate of J using Slater orbitals.