Calculation of optical line shapes for generalized multilevel vibronic systems

摘要

An approximate method for calculating the onehyphen;exciton Greenrsquo;s functions (and hence the linear response optical line shapes) of a multilevel excited electronic manifold is presented. Vibronic coupling to low and high frequency modes are treated by appropriate perturbative techniques; the resulting numerical algorithms are rapidly convergent and easily evaluated. For two excited levels and single vibrational mode, the method reduces (at lowest order) to previous approximations which have been extensively compared with basis set results.