L(3) ABSORPTION-SPECTRUM OF GERMANIUM SINGLE-CRYSTAL

The structure in L(3) absorption spectrum of Ge is obtained unambiguou sly by a total photoelectron yield measurement on a cleaved surface un der ultra high vacuum. The general feature of the spectrum around tile threshold is similar to both the BIS spectrum and the calculated DOS of the conduction band. The first peak appears similar to 0.6 eV lower in comparison with the BIS spectrum and the DOS. It suggests the exis tence of an excitonic effect due to a 2p core hole.