Higher approximations in the theory of isomer-isomer phototransformations of molecules

The method for calculating the probabilities of optical transitions between structural isomeric forms of molecules suggested earlier is extended to in clude the dependence of the electronic factors on basis electron-vibrationa l coordinates. The expansion of these factors in powers of isomer vibration al coordinates is considered. An approximate approach involving terms that correspond to overlap of the electronic functions of deformed isomer states is formulated.