Electronic structure of minerals: The apatite group as a relevant example

First principle methods for calculation of the electronic structure of mine rals is presently an emerging area of computation. In this article, a clust er approach compared with periodic boundary condition calculations based on local density approximation calculations is proposed for calculating the e lectronic structure of a mineral group. Validation of the approach is perfo rmed using two test cases: the fluoroapatite Ca-10(PO4)(6)F-2 and the neody mium britholite Ca9Nd(PO4)(5)(SiO4)F-2. Calculations of the electronic stru cture for both infinite crystals and clusters were performed using Kohn and Sham density functional theory in the local approximation. The deformation density map and density of states are computed for both solids, and Mullik en analysis is performed for clusters. (C) 2000 John Wiley & Sons, Inc.