Photodissociation dynamics of Cl2O at 235 nm using velocity map ion imaging

摘要

We have investigated the photodissociation dynamics of expansion-cooled C12O at 235 nm using photofragment velocity map ion imaging coupled with resonance-enhanced multiphoton ionization (REMPI) to measure the speed and angular distributions of the Cl(~2P_(3/2)) and Cl(~2P_(1/2)) products. We observe speed-dependent spatial anisotropy for both Cl fragments from the imaging data and attribute this to a fraction of nascent ClO, which undergoes secondary photodissociation. We have employed a Monte-Carlo forward-convolution scheme to analyze the data and obtain the speed distribution and anisotropy parameters for the ClO + Cl(~2P_(3/2,1/2)) channels. We find that the speed distribution of the Cl(~2P_(1/2)) + ClO channel is bimodal with an anisotropy parameter of 1.2 ± 0.2, whereas the speed distribution of the Cl(~2P_(1/2)) + ClO channel consists of a single component with an anisotropy parameter of 1.0 ± 0.2. We have determined branching ratios for Cl(~2P_(3/2)) + ClO and Cl(~2P_(1/2)) + ClOchannels to be 0.97±0.02:0.03±0.02. Based on the translational energy distribution of Cl(~2P_(3/2)) + ClO channel, 28% of the parent molecule undergoes three-body dissociation.