Photon-Energy Dependence of Excited-State Na Desorption from Na Halides by Synchrotron Radiation

摘要

Photon-energy dependence of excited-state Na desorption from NaF and NaCl has been investigated in the energy range covering the Na-2p level excitation. The excited-state alkali desorption from NaF is observed below the threshold of the core-level excitation. The excitation spectra of excited-state Na desorption show the peak corresponding to the Na L_(2,3) core-exciton band, and indicate that contributions of the core-level and of the valence-band excitations to the desorption are almost the same. Therefore, the Knotek-Feibelman mechanism based on the Auger process is not valid for the desorption of excited-state alkali atoms even in the core-level excitation.