Deciphering the dynamics and vector correlations of vacuum ultraviolet (VUV) photodissociation of CO2 at 155 nm | Poster Board #2620

The Vacuum Ultraviolet (VUV) photodissociation of CO₂ via the dominant O(¹D) channel near 155 nm were studied using Velocity Map Imaging (VMI) technique. Speed dependent vector correlations (the correlations among the transition dipole moment μ of the parent molecule, the recoil velocity vector v and rotational angular momentum vector j of the photofragments) were extracted. This was made possible via the application of a set of equation first developed by Grubb et al. And in combination with a Monte Carlo style simulation program and necessary approximations, full vector correlation information were extracted from the anisotropic angular distributions of the images. Our results indicated a picture of photodissociation mainly via the excited 2¹A’ (A) state. The transition dipole moment lies in the bent molecular plane. It is not parallel, but pointing away from the dissociating C-O bond. In addition, speed dependent μ-v correlation showed a clear trend, with higher rotationally excited CO correlating to larger angle between μ and the recoil direction. Such clear trend was successfully explained with a mathematical model (first developed by Reisler and coworkers) considering non-axial recoil effect. Although 1¹A” (B) state is also energetically available, we do not believe it is involved in this case.