Abstract
The minimum core energies of inequivalent perfect dislocations in α quartz with Burgers vector a1, a2or c and line direction a2or c are evaluated using a Keating-type valence force potential fitted to phonon dispersion curves. Dislocations that are dissociated or contain dangling bonds, valence alternation defects or non-stoichiometry are not considered. The low values of the core energies for the lowest-energy structure of each dislocation type, generally in the range 2·5 pV, appear to justify the last three restrictions, with the possible exception of c screw dislocations which should have core energies not lower than 6 eV. © 1984 Taylor & Francis Group, LLC.