  We introduce a new method to calculate Franck-Condon factors in polyatomic
molecules that is based on the tomographic probability approach to quantum
mechanics. This approach is implemented to calculate transition probabilities
in various systems under an instantaneous change of frequency and equilibrium
position of nuclei in a molecule by an external force. The problem is
considered for different types of the Dushinsky matrix and for any quantity of
atoms in a molecule.
