A 3-DIMENSIONAL WAVE-PACKET STUDY OF AR-CENTER-DOT-CENTER-DOT-CENTER-DOT-I-2(B)-]AR+I+I ELECTRONIC PREDISSOCIATION

A three-dimensional wave packet study of Ar ... I-2(B)--> Ar + I(P-2(3 /2) + I(P-2(3/2)) electronic predissociation, arising from the argon-i nduced electrostatic coupling between the B((3) Pi(0+u)) and the repul sive a((3) Pi(1g)) state of I-2, is presented. A time-dependent golden rule approach is used. The initial wave packet corresponds to a bound vibrational wave function of the Ar ... I-2(B) complex (with zero tot al angular momentum) multiplied by the electronic coupling. A 3-D prop agation in the final dissociative surface is then performed and the pr edissociation rates are obtained by Fourier transform of the wave pack et autocorrelation function. The potential energy surfaces are describ ed by sums of atom-atom interactions. For the B((3) Pi(0+u)) state pot ential, empirically determined van der Waals parameters available from the literature are used. For the final dissociative a((3) Pi(1g)) ele ctronic state, the van der Waals parameters are adjusted to reproduce the experimentally observed oscillations of the electronic predissocia tion rate as a function of the initial vibrational quantum number upsi lon' of I-2. It is shown that good agreement between calculated and me asured values can be obtained with a van der Waals well of 100 cm(-1) and an interstate coupling of the order of 14 cm(-1). (C) 1996 America n Institute of Physics.