A Comparison of radiationless transitions involving single-minimum and double minima potential energy surfaces

The quantum-statistical-mechanical (QSM) approach to molecular relaxation phenomena is employed to compare radiationless transitions originating from an electronic state characterized by a single minimum and double minima potential surface for a vibronically active, non-totally symmetric mode. The vibronic level dependence of the decay rates of these two cases has been investigated for both small and large energy gap transitions. It is shown that the behavior of a molecular system is quite different for an initial state possesing a double minima potential surface as compared to the case in which the initial state possesses a single minimum.