Classical and quantum studies of the photodissociation of a HX (X=Cl,F) molecule adsorbed on ice

Abstract

The photodissociation dynamics of a HX (X = Cl,F) molecule adsorbed on a hexagonal ice surface at T = 0 K is studied using time-dependent quantum wave packets and quasiclassical trajectories. The relevant potential energy surfaces are calculated using high-level ab initio methods. We present here two dimensional calculations for the dynamics of the hydrogen photofragment for both HCl and HF molecules. The purpose of this paper is to compare the photodissociation dynamics of the two molecules which are adsorbed on the ice surface with different equilibrium geometries. The total photodissociation cross section and the angular distribution are calculated. The comparison with classical trajectory calculations provides evidence for typical quantum effects and reveals rainbow structures.

Erratum: “Classical and quantum studies of the photodissociation of a HX (X=Cl, F) molecule adsorbed on ice” [J. Chem. Phys. 127, 164717 (2007)]

“…For the less intense peaks, only two of them remain ͑␥ = 19°and ␥ = 86°͒ compared to the five small peaks observed ͑Ϫ36°, Ϫ4°, 19°, 23°, and 86°͒ in our previous calculations. 1 Again, we obtain a very good agreement between the two descriptions for the background of the distributions except, between 40°and 70°where the quantum interferences pattern disappear in the classical results. Finally, to conclude, we note that even if the new classical distributions are slightly different from the previous ones, the physical interpretation of the dynamical process is, however, still valid.…”

“…1͒, as mentioned in our previous paper. 1 Obviously in the classical distributions the peaks due to quantum interference effects disappear. For the HF/ice system, we still observe a fairly good agreement between quantum and classical distributions.…”

“…4 for the HF/ice system and are compared with our previous quantum results. 1 classical, the shape of the distribution being only due to the potential energy surface corrugation without any quantum interference effects. Between 60°and 90°only one peak around 75°is present in the classical angular distribution.…”

Ultrafast photochemistry of methyl hydroperoxide on ice particles

“…There are many precedents of using molecular dynamicsbased approaches for investigating photochemistry in condensed environments (26)(27)(28)(29)(30)(31) and using small water clusters as representative model systems of aqueous reactivity (32,33). For example, photolysis of water in crystalline ice was examined by using force fields to approximate the potentials (26).…”

“…For example, photolysis of water in crystalline ice was examined by using force fields to approximate the potentials (26). Photodissociation of HCl adsorbed on ice was studied with an approach in which the hydrogen fragment was described quantummechanically and the chlorine fragment and the water molecules were treated classically (27,28). A similar quantum mechanics/ molecular mechanics strategy was used to investigate the photodissociation of chlorine peroxide on ice (29).…”