Observation of Extremely High Vibrational Excitation in O2 from Inelastic Scattering of Rydberg H Atom with O2.

Abstract

The state-resolved differential cross sections for the Rydberg-atom (RA) inelastic scattering process H*(n = 46) + O2(v = 0, j = 1,3) → H*(n') + O2(v', j') have been measured by using the H-atom Rydberg tagging time-of-flight (HRTOF) technique. Extensive vibrational excitation of O2 products has been observed at the two collision energies of 0.64 and 1.55 eV. Experimental results show that the O2 products in the low vibrationally excited states are clearly forward-scattered, whereas those in the highly vibrationally excited states are mainly backward-scattered. Partially resolved rotational structures were also observed and assigned. The striking observation of extremely high energy transfer from translational to vibrational excitation at the backward direction could be explained involving charge transfer between proton and O2 molecule and possibly complex formation during the scattering process.