Dynamics and vector correlations of vacuum ultraviolet (VUV) photodissociation of CO2 at 155 nm

Abstract

In this work, the CO₂ Vacuum Ultraviolet (VUV) photodissociation dynamics of the dominant O(¹D) channel near 155 nm have been studied using Velocity Map Imaging (VMI) technique. Correlations among the transition dipole moment of the parent molecule, recoil velocity vector and rotational angular momentum vector of the photofragments were extracted from the anisotropic angular distributions of the images. The vector correlations extracted indicated a picture of photodissociation mainly via the excited 2¹A′ (A) state. The transition dipole moment lies in the bending molecular plane, and the is pointing perpendicular to the plane, while the μ–v vectors angle is between 41°–45°. In addition, a clear trend was observed. As the product CO rotational state j increases, the spatial anisotropy parameter (β ≡ 2β²₀(20)) decreases. This j-dependent attenuation of spatial anisotropy parameter can be explained mainly with the consideration of non-axial recoil effect. These results are in good agreement with both theoretical work and previous experimental work.