Characteristics of electron density distributions in metal oxides

The electron density distributions in a series of metal oxides are calculated using the DV-Xalpha molecular orbital method. It is found that the logarithm of the electron density, logrho(r), decreases with the distance, r, from the oxygen nucleus, while keeping a constant slope relevant to oxygen atom. The magnitude of the slope is about 15.75 for O-1s electrons, and about 6.61 for O-2s, 2p electrons being nearly close to the respective values of 16 and 8, expected from the radial distribution functions of hydrogen-like atom containing only one electron. The extent of the region for the O-2s, 2p electrons changes with metal species in the oxides, but the slope remains unchanged. Furthermore, it is shown that the nature of the chemical bonding is well represented in 109 (rho(min)Z(-3)) VS. 2(Z/n) r(min) in plots, where rho(min) is the minimum electron density, r(min) is the distance r at rho(min), Z is the atomic number, and n is the principal quantum number.