Mixed quantum/classical dynamics of photodissociation of water and argon-water

We present multiple configurational mixed quantum/classical studies of the photodissociation dynamics of H2O (à ← X˜) and Ar-H2O (à ← X˜). In this approach, the dynamics of the argon atom and one of the hydrogen atoms are treated classically, while the dynamics of the remaining OH molecule are treated quantum mechanically. The quantum subsystem is further divided into two or more coupled contributions and separately propagated in the classical trajectory dynamics to obtain accurate results. The accuracy of the multiple configurational mixed quantum/classical method is tested against an exact quantum treatment of H2O photodissociation on the à state. We obtained good agreement between the OH rotational distributions and photodissociation cross section obtained by the two approaches. Vibrationally mediated photodissociation dynamics of Ar-H2O has been studied by this method and compared with experimental results. By comparing the rotational distribution of the OH product obtained from photodissociation of Ar-H2O and H2O, the influence of the Ar atom on the photolysis process can be regarded as a spectator in intracluster collision. The simulation provides an insight to the dynamics of photodissociation in clusters.