Bound-free fluorescence of rare gas hydrides

Abstract

Bound-free fluorescence of HeH, NeH, ArH, KrH and XeH is reported. The excimers are formed via a photochemical reaction between H 2(C 1Π u, B 1Σ u +) and rare gases following excitation with synchrotron radiation. Broad fluorescence continua in the near UV are observed and assigned to the rare gas hydride transition B 2π→ X 2Σ +. In the case of NeH, the A 2Σ + state also contributes to the fluorescence spectrum. Experimentally derived binding energies for the B state and bound-free spectra of HeH and ArH are in good agreement with recent ab initio calculations. Radiative lifetimes, quenching cross sections and formation cross sections have also been determined.