Infrared fluorescence of Xe-2 molecules in electron/proton beam excited pure Xe gas and in an Ar/Xe gas mixture

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 less than or equal to lambda less than or equal to1.8 mum. In the previously unexplored range for lambda greater than or equal to1.05 mum we have detected a broad continuum near-infrared fluorescence centered at lambda approximate to1.3 mum. 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 Xe-2 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. (C) 2001 American Institute of Physics.