High-Resolution Imaging Study on Photodissociation of OCS⁺ [A²Π_Ω=1/2,3/2 (ν₁ 0 ν₃)]

The development of the velocity map ion imaging (VMI) technique has greatly advanced the study of photodissociation dynamics. The high-resolution imaging study of the photodissociation allows for the acquisition of precise and detailed information on the fragments. This information can further provide more insight into the energy partition and potential pathways involved in the photodissociation process. In this study, we report the investigation on the photodissociation of OCS⁺ via the A²Π_Ω=1/2,3/2 states following the excitation of A²Π (ν₁ 0 ν₃) ← X²Π (0 0 0) by using time-sliced VMI techniques in the ultraviolet region. Our investigation revealed significant mode-dependent recoil anisotropies and branching ratios of two product channels for both Ω = 1/2 and Ω = 3/2. The photolysis products also exhibited dramatic deviation in angular distributions and generally comparable kinetic energy distributions following the excitation to the same vibrational modes of A²Π_Ω states with two separate spin-orbit components. According to the observation in this study and previously reported photodissociation mechanisms of the OCS⁺ cations, the decay from the A²Π_3/2 state was more likely via the internal conversion to high rovibrational states of the X²Π state, in comparison to the A²Π_1/2 state.