The optical potential for Ne*(3P2,0) + CO chemi-ionization reactions: Nature of the intermolecular forces and selective formation of CO+ in ground (2Σ) and excited (2Π) electronic states

Abstract

Ionization processes, promoted by the collisions of CO molecule with noble gas atoms electronically excited in a metastable state, as Ne*, are known as chemi-ionization (CHEMI) reactions. CHEMI reactions of CO have been experimentally investigated in various laboratories exploiting the molecular beam technique, which allowed the resolution of single collision events. The present study, exploiting a proper formulation of optical potential that drives the collision dynamics, provides an internally consistent rationalization of the experimental findings. Such formulation emphasizes the change of both real and imaginary parts of the optical potential along each permitted reaction channel leading to the formation of CO+ in the ground (X2Σ) and in the first excited (A2Π) electronic state. In particular, some basic details, up to now unknown, on the dynamical evolution of reagents toward products, along the manifold of state-to-state reaction channels, have been properly emphasized. Obtained information appears of general interest for many other reactions, which, respect to CHEMI, are more difficult to characterize in detail.