López-López S, Prosmiti R, García-Vela A. Quantum treatment of the Ar-HI photodissociation dynamics.
J Chem Phys 2004;
121:1802-9. [PMID:
15260731 DOI:
10.1063/1.1767092]
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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.
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