Energy loss of 18 keV electrons in gaseous T and quench condensed D films

Abstract

Measurements of the energy loss of fast electrons at an energy of 18 keV have been performed on molecules of hydrogen isotopes, gaseous T 2 and frozen D 2 . Whereas in the case of gaseous T 2 the values of total inelastic cross-section ( cm2 for E = 18.6 keV), average energy loss ( eV) and peak position of the energy loss spectra ( eV) agree well with the expectations, the corresponding values for quench condensed D 2 differ significantly from the ones for gaseous T 2 . We observe a significant lower total inelastic cross-section ( cm2, for E = 18.6 keV) larger average energy loss ( eV) and higher peak position ( eV). These differences may be interpreted in terms of changes of the final state spectrum. A CI calculation for a D 2 cluster shows indeed a clear shift of the excited states in agreement with the observation.