CHEMICAL-BINDING ENERGY OF POINT-DEFECTS IN BCC TRANSITION-METALS

The chemical binding energy of two point defects in paramagnetic b.c.c. metals is estimated in the generalized double-scattering scheme of Gautier, Moraitis and Parlebas (1976). For pairs consisting of an interstitial and a (i-metal impurity, and also an sp impurity and a d impurity, calculation yields a strong variation of the binding energy with the filling of the b.c.c. host bands. If ΔZ is the difference in charge between the substitutional d impurity and the matrix ion-cores, it is shown that, for small values of ΔZ, the binding energy is proportional to ΔZ. For ΔZ greater than 1, this perturbing limit breaks down and a complete calculation has been made. © 1979 Taylor & Francis Ltd.