NORMAL-MODE ANALYSIS FOR A COMPARATIVE-STUDY OF RELAXATION PROCESSES OF CHARGE-TRANSFER AND PHOTOEXCITATION IN C60

In this article we employ a normal mode analysis to the relaxation pro cesses of charge transfer and photoexcitation in C-60 It is found that only a few H-g modes, the so-called dominant modes, play a critical r ole in the relaxation, which may imply that only a few H-g modes can h ave a strong electron-phonon coupling constant. This is consistent wit h recent experimental results, although previous calculations reported that almost all the H-g modes have roughly the same coupling constant . Those dominant modes control mainly the early and the later behavior s and determine the relaxation times of the processes, The difference between the relaxation times of charge transfer and photoexcitation ca n also be understood from the dominant modes, We discover that the eig envectors of the dominant modes are very unique, i.e., if the bond len gths are altered along the eigenvectors, one can observe a change in t he lattice by a typical laminar distortion structure. (C) 1997 America n Institute of Physics.