State selected ion–molecule reactions by a TESICO technique. IV. Relative importance of the two spin-orbit states of Ar+ in the charge transfer reactions with N2 and CO

Abstract

Charge transfer reactions Ar⁺ (²P_J)+N₂→N⁺₂+Ar (1) and Ar⁺(²P_J)+CO→CO⁺+Ar (2) have been studied for the two spin‐orbit states (J = 3/2 and 1/2) separately using the threshold electron‐secondary ion coincidence (TESICO) technique. Relative cross sections for the two states σ(3/2) and σ(1/2) have been determined at three collision energies 0.2, 1.4, and 5.8 eV. It has been found that in Reaction (1), σ(3/2) is larger than σ (1/2) with ratio σ(1/2)/σ(3/2) ranging from 0.5 to 0.8 depending on the collision energy, whereas in Reaction (2), σ(1/2) is larger than σ(3/2) with the ratio ranging from 1.2 to 1.6. The implications of these results are discussed with regard to the roles of energy resonance and Franck–Condon factors in charge transfer processes.