A complete quantum mechanical study of chlorine photodissociation

Abstract

A fully quantum mechanical dynamical calculation on the photodissociation of molecular chlorine is presented. The magnitudes and phases of all the relevant photofragment T-matrices have been calculated, making this study the computational equivalent of a "complete experiment," where all the possible parameters defining an experiment have been determined. The results are used to simulate cross-sections and angular momentum polarization information which may be compared with experimental data. The calculations rigorously confirm the currently accepted mechanism for the UV photodissociation of Cl(2), in which the majority of the products exit on the C(1)Π(1u) state, with non-adiabatic couplings to the A(3)Π(1u) and several other Ω = 1 states, and a small contribution from the B(3)Π state present at longer wavelengths.

The vibrationally mediated photodissociation of Cl2

“…The theoretical procedure used here to investigate the photodissociation of vibrationally excited Cl 2 is identical to the method set out by Balint-Kurti and co-workers for the photodissociation of the hydrogen halides [15][16][17][18][19] and the recent study on the photodissociation of Cl 2 (v = 0), 10 and only the principles and key equations are described here. The fully quantum mechanical method seeks to solve the timedependent Schrödinger equation,…”

“…As described in Ref. 10, the calculation was performed on a set of 10 ab initio potential energy curves. 11 The potentials included in the calculation, in both the diabatic and adiabatic representations, are shown in Fig.…”

“…To our knowledge, there has been only one previous determination of the atomic polarization following the photodissociation of Cl 2 (v = 1), by Zare and co-workers, 8 and that was performed at a single wavelength of 470 nm. In a recent paper, 9 experimental results following the photodissociation of Cl 2 (v = 0) at a range of wavelengths were compared to the results of timedependent wavepacket calculations 10 performed on a set of high level ab initio potential energy curves. 11 The experimental results, which included the first determination of high order (K = 3) electronic orientation moments of Cl( 2 P 3/2 ) atoms, were, in general, in good agreement with the high level theory.…”

“…11 The experimental results, which included the first determination of high order (K = 3) electronic orientation moments of Cl( 2 P 3/2 ) atoms, were, in general, in good agreement with the high level theory. In the present work, the recent time-dependent wavepacket calculations 10 are extended to encompass the photodissociation of vibrationally excited Cl 2 (v = 1), in order to compare with experimental measurements.…”

“…IV, where they are compared with the experimental measurements made here, and with the recent theoretical study on the photodissociation of Cl 2 (v = 0). 10 The paper concludes with a short summary and suggestions for topics of future study.…”