Association energy of divalent and monovalent impurities with edge dislocations in NaCl

Abstract

In the present paper calculations have been made of the association and interaction elastic energies for monovalent cation impurities and divalent cation impurities unassociated and associated with cation vacancies in the form of dipoles with dislocationsa/2 〈110〉. {110} anda/2〈110〉 {100} in NaCl. The results obtained for the chosen positions in dislocation cores show that a) among the unassociated divalent impurities considered the increase in barium concentration around dislocations takes place in the extended region of dislocations and the increase in calcium and other impurity concentration with\(r_{ + + }< r_{Ca^{ + + } } \) in the compressed region of dislocation, mainly on the dislocationa/2〈110〉 {100}. In the case of divalent impurities associated with cation vacancies in the form of dipoles the increase in impurity concentration can take place at all impurities as in the above mentioned case and additionally Sr++ b) the increase in monovalent impurity concentration (r+>164-01) around dislocations takes place, excepting lithium, in the extended region of the dislocation of both types. Our calculations are compared with the published experimental data.