Infrared fluorescence of Xe2 molecules in electron/proton beam excited pure Xe gas and in an Ar/Xe gas mixture

Abstract

We report experimental results of proton- and electron-beam-induced near-infrared fluorescence in high-pressure Xe gas and in a 90% Ar–10% Xe gaseous mixture at room temperature. The investigated wavelength band spans the range 0.7⩽λ⩽1.8 μm. In the previously unexplored range for λ⩾1.05 μm we have detected a broad continuum near-infrared fluorescence centered at λ≈1.3 μm. The continuum shifts towards longer wavelengths as pressure is increased up to 1.5 MPa. The shift is quantitatively different in pure Xe or in the mixture, but qualitatively similar. We believe that this continuum is produced by a bound-free Xe2 excimer transition in a way similar to the well-known first and second vacuum ultraviolet continua of noble gas excimers. The pressure-dependent shift can then be explained by the interaction of the outer electron in the excimer with the atoms of the host gas.