Guided-ion beam measurements of the O+(4S)+Xe charge-transfer reaction

Abstract

Guided-ion beam integral cross section measurements, product ion time-of-flight (TOF) measurements, and doubly differential cross sections are presented for the O+(4S)+Xe→O+Xe+ charge-transfer reaction. The integral cross section is observed to increase monotonically with mean center-of-mass collision energy (ET) from 0.72 Å2 at 0.1 eV to 26.9 Å2 at 35.2 eV. Product ion TOF measurements show that the primary contribution to the charge-transfer cross section arises from a direct electron transfer at long range of the Demkov type. The collision energy dependence of the cross section for center-of-mass (c.m.) forward-scattered Xe+ ions reveals that this minor contribution to the total cross section arises from a hard-sphere-type scattering that primarily involves a Landau–Zener-type diabatic curve crossing at shorter range. Doubly differential cross sections at 4.4 eV indicate that translational to product internal energy transfer is inefficient even at small impact parameters and that the spin-allowed Xe+(2P)+O(3P) product channels are preferentially populated.