The predissociation dynamics from low vibrational levels of the B electronic state of the HeBr2 and NeBr2 van der Waals molecules was studied using time-resolved optical pump-probe spectroscopy. The predissociation rates from these levels do not simply increase monotonically with increasing vibrational quantum number as predicted by the energy gap model for direct vibrational predissociation. Instead the rate oscillates as a function of quantum number, and the pattern of the oscillations is the same for both complexes. We attribute this to an electronically nonadiabatic process in competition with vibrational predissociation. Based on calculations of the Franck-Condon overlap between the B electronic state and other dissociative electronic states in the region of interest, we predict that electronic predissociation occurs from either the 3?g (1g) or (2g) state. The electronic predissociation rates we extracted are proportional to the Franck-Condon factors.

Competition between electronic and vibrational predissociation in the HeBr<sub>2</sub> and NeBr<sub>2</sub> van der Waals molecules

239th National Meeting (2010)

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Competition between electronic and vibrational predissociation in the HeBr2 and NeBr2 van der Waals molecules

Competition between electronic and vibrational predissociation in the HeBr₂ and NeBr₂ van der Waals molecules