ALL-ATOM AB-INITIO ENERGY MINIMIZATION OF THE KAOLINITE CRYSTAL-STRUCTURE

Calculations that minimize the energy and optimize the geometry of all atomic coordinates for two proposed kaolinite crystal structures were performed using a first-principles, quantum chemical code based on lo cal density functional theory. All calculations were performed using p ublished unit-cell parameters. Inner- and interlayer H atom positions agree well with those determined by Bish (1993) from neutron diffracti on data and confirm a unit cell with C1 symmetry.