Absorption Spectra of Rubidium Halides in the Extreme Ultraviolet

Abstract

Absorption spectra of thin films of all rubidium halides are investigated at room an liquid nitrogen temperatures in the energy range 12–30 eV. Synchrotron orbital radiation at INS-Tokyo was used as a continuum light source. Several sharp peaks are found in the range 16–19 eV. When samples are cooled to liquid nitrogen temperature, two of them shift towards high energy, while three of them towards low energy. The former are attributed to the excitons composed of Rb+4p hole and the s-like electron, while the latter are attributed to those composed of Rb+4p hole and the d-like electron. The multiplicity of the exciton peaks is discussed in terms of the band model and the atomic model.