Imaging CO₂ Photodissociation at 157 nm: State-to-State Correlations between CO(ν) and O(³P_{<i>j</i>=0,1,2})

Abstract

The spin-forbidden CO(ν) + O(3Pj) channel produced by 157 nm photodissociation of CO2 was investigated by velocity map imaging. O(3P) images were measured for the three 3Pj spin−orbit states (j = 0, 1, and 2), and the CO vibrational-state distributions that correlate to the O(3Pj=0,1,2) spin−orbit product were determined. Nearly all energetically allowed product CO(ν) levels (i.e., ν ≤ 8) are observed, with minor differences in the CO vibrational distributions for the three channels. The angular anisotropy, which also shows minor differences for the three j channels, is found to decrease with increasing CO vibrational excitation, suggesting that the lower vibrational states are produced by photodissociation from a more linear OCO geometry. Fits to the total kinetic energy distributions suggest that the CO rotational energy is relatively cold. The overall results further suggest that the three spin−orbit pathways are not mixed completely in the exit channel.