Quantum treatment of the Ar-HI photodissociation dynamics

Abstract

A wave packet simulation of the ultraviolet photolysis dynamics of Ar-HI(upsilon = 0) is reported. Cluster photodissociation is started from two different initial states, namely, the ground van der Waals (vdW) and the first excited vdW bending state, associated with the Ar-I-H and Ar-H-I isomeric forms of the system, respectively. Formation of Ar-I radical products is investigated over the energy range of the cluster absorption spectrum. It is found that the yield of bound Ar-I radical complexes is typically 90%-100% and 70%-80% for the initial states associated with the Ar-I-H and Ar-H-I isomers, respectively. This result is in agreement with the experimentally observed time-of-flight spectrum of the hydrogen fragment produced after Ar-HI photodissociation. The high Ar-I yield is explained mainly by the small amount of energy available for the radical that is converted into internal energy in the photofragmentation process, which enhances the Ar-I survival probability. Quantum interference effects manifest themselves in structures in the angular distribution of the hydrogen fragment, and in pronounced rainbow patterns in the rotational distributions of the Ar-I radical.

Effect of the Excitation Energy on the (HI)2 Nonadiabatic Photodissociation Dynamics

“…The effect of increasing E does not affect the position of the oscillations at low j states, only causing the appearance of new oscillations at higher j . It is stressed that similar rotational interference patterns have been found in the rotational distributions of Kr−Br and Ar−I radical fragments produced upon photodissociation of Kr−HBr and Ar−HI clusters.…”

Wave packet study of the UV photodissociation of the Ar2HBr complex

“…While most of the studies were devoted to the one-atom cage effect ͑Rg-HX͒ [1][2][3][4][5][6][7][8][9][10][11][12][13][19][20][21][26][27][28][29][30] or to the cage effect in or on large clusters where the first solvation shell is closed ͑Rg n with n ജ 12͒, [15][16][17]22,23,25,[31][32][33] relatively little attention has been paid to the cage effect in the Rg n -HX systems with 1 Ͻ n Ͻ 12, and the corresponding investigations concern uniquely the Ar n -HF and Ar n -HCl complexes. In particular, the capacity of an inert environment to hinder the photodissociation ͑and even cause, sometimes, recombination͒ of a solute molecule, also called cage effect, is a well-known and challenging topic.…”