The charge transfer dynamics study for He⁺- Diatoms interactions

Ion-molecule collisions are dominant processes in the interstellar (ISM) and interplanetary (IPM) medium [1]. Such collisions proceed through various elastic and inelastic channels. The study plays an immense role in astrophysics, especially in the cometary and planetary atmosphere, atmospheric physics, and plasma and fusion science. The collision study of major constituents of ISM and IPM ions such as H⁺, He⁺, and He²⁺ with minor neutral molecules (H₂, CO, N₂, NO, O₂, and CO₂) has gained a lot of interest due to its astrophysical relevance [2]. Solar wind ions move from 200 km/s to 700 km/s, showing charge exchange phenomena at the high collision energy [3]. Many experimental and theoretical studies have been carried out over the years to understand such phenomena [4-6]. The idea is to understand the interaction of ions present in the ISM and cometary atmosphere with the small molecules from the quantum mechanics perspective. Our work is focused on the ab initio quantum dynamics study of He⁺- diatom charge transfer (CT) reactions. The high ionization potential of He⁺ allows a large number of CT product channels accessible. We computed the adiabatic potential energy surface (PESs) and identified the respective product channels (entrance and CT). Several low-mixing excited electronic PESs also interact demanding the non-Born-Oppenheimer treatment for dynamical studies. The CT reactions seem to happen through nonadiabatic coupling between the PESs. Our current focus is on the theoretical development to study the several dynamical outcomes leading to CT in the systems.

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