On the Electronic States of the Doubly-charged Negative Ions of Oxygen in Oxide Crystals

Abstract

The Oxygen atoms are supposed to become the doubly-charged negative ions within oxide crystals. There is, however, no experimental evidence of the existence of such ions in gas phase, which fact suggests us that they are probably very unstable in the free state. We, therefore, may reasonably suppose that they are stable only within oxide crystals due to the effects of the surrounding ions. In order to elucidate the above situation quantitatively, we have here attempted to work the electronic states of the oxygen ions within the oxide crystals by the variational method, which we adopted already for the calculation of the cohesive energy of LiF. Thus, we have confirmed, for MgO, that the doubly-charged negative ion of oxygen may be actually stable in such crystals. Furthermore, we have calculated also the electronic affinity of the ions and diamagnetic susceptibility of MgO crystals, which results seem to show rather good agreements with the experimental observations as fat as our computational accuracy doe...