Auger-free luminescence excitation spectra in CsCl and CsBr between 50 and 140 eV

Abstract

Photo-excitation spectra and decay curves for the radiative transitions of electrons from the valence band to the next deeper outermost 5p core holes of Cs + have been measured for CsCl and CsBr. The excitation spectra are anti-correlated with respect to the reported absorption spectra. The luminescence intensity decays faster when incident photons are absorbed at distances of the order of 200 Å from the surface than when they are absorbed in the bulk at ≳ 2000 A ̊ from the surface. These observations show that the 5p outermost core holes produced by incident photons near to the surface relax nonradiatively more rapidly than those in the bulk.