The soft X-ray spectroscopy of solids, II. Emission spectra from simple chemical compounds

Abstract

K - and L -emission bands, emitted in the soft X -ray region of the spectrum by atoms in a number of chemical compounds, have been investigated. The substances for which such spectra are available through the present or previous work are: fluorides, chlorides, bromides, iodides; oxides, sulphides; boron nitride and other boron com pounds; and carbides. In the cases of SiC, BN and a number of oxides, spectra from both the component atom s forming the com pound have been obtained. The results are interpreted, as those for metals and element-insulators have been in a previous paper (Skinner 1940), to give the characteristics of the bands of levels which exist for the valence-electrons in the normal state of the substance. In the case of the halides, data on the p - and s -levels of the negative ions are given, and it is shown that, even in this case, the crystal structure leaves its mark on the form of the bands of levels. The 2 p -bands of oxygen from most oxides are more spread-out on an energy scale, thus showing that the interaction between electrons in neighbouring atoms is considerable. The spectra of the metal ions in oxides are very complex, and an attempt is made to disentangle the factors which lead to this complication. In doing so, it is hoped that we may have thrown some light on the difficult subject of the structure of semi-polar compounds in solid form.