Due in no small part to its complexity, internal conversion is effected by a myriad of different photophysical properties and system specifics. The energy gap, temperature, medium, degrees of freedom, streic bulk, Franck-Condon factors, thermal occupation, electronic charge; all can influence the overall rate of internal conversion through intricate parametric relationships. Duschinsky rotations, or the Duschinsky effect , where frequency of a particular normal mode will shift in energy drastically with respect to which electronic energy level it is observed due to mixing of modes with respect to the ground state, recognised as the reason for the subtle asymmetry between absorption and emission spectra in a variety of systems , can shift the Franck-Condon factors quite drastically .