TEMPERATURE DEPENDENCE OF PHOTOSYNTHETIC EXCITATION TRANSFER—ACTIVATIONLESS TRANSFER

Abstract— We have investigated the temperature dependence of photosynthetic excitation transfer by quantum-mechanical treatment. Our theoretical analyses predict that the temperature dependence of most excitation transfers is quite weak in the relatively high temperature range (kT 100cm^-1), whereas some excitation transfers exhibit complex temperature dependence in the low temperature range due to the environmental effect. The temperature-independency in the high temperature range results from the fact that most excitation transfers among various Chi forms characterized by different absorption peaks almost satisfy the activationless condition where the energy gap for the excitation transfer matches with the nuclear rearrangement energy. This activationless condition, which has already been noticed in the electron transfers in the reaction center, is suggested to play central roles in the efficient energy conversion in the primary stage of photosynthesis.