2013 Volume 12 Issue 2 Pages 95-100
This article investigates the relationship between the characteristic radii from an anion nucleus, by comparing RSP (the Shannon−Prewitt anion radius based on Pauling's theory with Goldschmidt's experimental data) with Req, at which the charge densities of one anion and cation respectively are equal in the interatomic region in an ionic crystal. Calculations were performed via the SIWB (surrounding or solid Coulomb-potential-induced well for basis set) method reported previously using the discrete variational (DV) molecular orbital method in a density functional theory (DFT) scheme. Numerical basis atomic orbitals were derived via the method introduced by the present author in a previous paper, in which a spherically symmetric well potential generated by the crystal Coulomb potential was added solely to the potential for electrons within the anion radius on the isolated anion. The radius Req for the well radius was determined to satisfy the conditions that the input value of the well radius for the anion coincides with the output value of Req after sequential repetitions. The analysis also obtained the radius Rmin, where the sum of the above two charge densities takes the minimum. It was clear that Req is relatively similar to the Shannon−Prewitt anion radius.
