VACANCY INDUCED ELECTRONIC STATES IN SOME TANTALUM CARBIDE, BORIDE, NITRIDE, SILICIDE AND BOROCARBIDE POWDERS: AN X-RAY EMISSION STUDY

Abstract

The L and M X-ray emission spectra of tantalum carbide, boride. nitride, silicide, aluminide and tantalum-hafnium carbide were found to be complex in nature. These spectra were analysed by a curvefit programme and were found to have three peak structure. The intensity of Lα2 emission was found to deviate very much from the theoretically predicted intensity. Beside, the main Lα1 emission around 8115 eV, emission peak around 8145 eV was also observed due to Lα1 emission. The chemical shift of Lα2 emission and the variation in its intensities for different compounds as well as the intensities of satellite emission line have been explained on the basis of Coster-Kronig processes leading to vacancy creation, shake off probabilities and molecular orbital formation taking place in these compounds.