FLUORINE-K-ALPHA AND CHLORINE-K-BETA EMISSION-SPECTRA FROM ALKALI FLUORIDES AND CHLORIDES

The fluorine-K-alpha and chlorine-K-beta emission spectra in fluorescence from a series of alkali halides MX (M = Li, Na, K, Rb and Cs; X = F and Cl) are measured with a high-resolution two-crystal spectrometer. Solid-state effects are observed on the intensities of the K1L1 and K-beta-x satellite peaks in the K-alpha and K-beta emission spectra, respectively. An anomalously low intensity of the K1L1 satellite peak is observed for KF. The measured emission spectra are presented along with the UPS spectra of the F- 2p and Cl- 3p valence bands obtained by Poole et al., the fluorine K absorption-edge spectra by Nakai et al. and the chlorine K absorption-edge spectra by the author. By using these spectra, the first shoulder at the K absorption edge is identified as being due to a core exciton, the energy level of which is formed below the bottom of the conduction band. The binding energy of the exciton is estimated.