Knowledge Bank

Expressions will be presented for calculating Franck-Condon factors in the harmonic approximation for transitions from a liner ground state to a bent excited state. These Expressions are similar to those published previously by $Doktorovet.al.a$ for the case where the number of modes does not change between the two states. The derivation of these equations will be briefly discussed. They will be applied to several test cases, including electronic transitions in diacetylene, $C4H2$.