Abstract
Following an earlier paper on the application to dislocations of the Keating potential adapted for α-quartz, an extension of the potential that includes a mutual repulsion for oxygen ions is presented. This additional feature prevents the inward collapse of the cores of screw dislocations, particularly PSH, but does not have a strong effect on other dislocations. Two new types of dislocation with Burgers vector c and line direction a are included. It appears that none of the 15 dislocations relaxed with the new potential gives rise to deep states. © 1985 Taylor & Francis Group, LLC.