ELECTRON-DISTRIBUTION IN MGO PROBED BY X-RAY-EMISSION

The relative intensity of the Mg K beta emission band with respect to the K alpha atomic line, obtained by electron-induced x-ray emission s pectroscopy, is used to investigate the variation of p-like valence el ectron number located around magnesium in metal and MgO. Calculated sp ectral intensities of Mg K emissions are obtained within the augmented plane-wave method for the perfect crystal. From experimental and theo retical data, the number of 3p electrons present around Mg and involve d in the K beta transition does not vary much with the metallic or ion ic character of the bonds. This result shows that the charge transfer is weak in the oxide. These experiments can be generalized to other co mpounds. Spectral densities of states (DOS) around Mg and O are also p robed and agreement is found between experimental and theoretical spec tral densities of 3p Mg and 2p O states. Changes of MgO valence DOS wi th annealing, etching, and aging are discussed. [S0163-1829(98)12419-0 ].