Competition between electronic and vibrational predissociation in Ar–I2(B): a molecular dynamics with quantum transitions study Original Research Article

A theoretical study of the competition between vibrational and electronic predissociation of the Van der Waals complex Ar⋯I2(B) using the Molecular Dynamics with Quantum Transitions (MDQT) method of Tully, is presented. The electronic predissociation is modeled by surface hopping from the B to the a state with probabilities given by the Franck–Condon factors between them. The vibration of I2 is treated quantum mechanically using a Discrete Variable Representation (DVR) while the relative motion of the Ar atom with respect to I2 is treated classically. The agreement between calculated and measured predissociation rates is very good. Analysis of the results indicate that first order rate equations are not adequate to describe the time dependent signals. This is due to the dependance of the electronic predissociation rates on the vibrational quantum number of the intermediate states of the process.