Vibrational Levels and Dissociation Processes of Rare Gas Dimer Ions Physics Division

Abstract

Threshold photoelectron spectroscopy is a useful tool for measuring vibrational levels of rare gas dimer ions. In this short review, features of threshold photoelectron spectroscopy are introduced. After that, the observed vibra-tional levels of Ar₂⁺ are described in detail. Explanations for the vibrational levels of KrXe⁺ measured by threshold photoelectron-photoion coincidence technique are also given. In the subsequent study, it is revealed that the II (1/2g) states of Kr₂⁺ and Xe₂⁺ completely dissociate via optical transitions to the repulsive I (1/2g) states, while that of Ail does not dissociate. Precise analysis of the time-of-flight spectrum for the Kr₂⁺ fragment from the Kr₂⁺ II (1/2u) state is also shown. The potential energy curve of the I (1/2g) state and the lifetime of the optical transition from the II (1/2g) state to the I (1/2g) state are obtained from this analysis.