Abstract
An empirical correlation is proposed between the vacancy parameters and the valence bond strength. The valence bond strength is defined as the ratio of the cohesive energy, Es, to the chemical valency, V. It is shown that the energy for vacancy formation (Ev) and the activation energy for self-diffusion (Q) can be expressed as Ev=A(Es⁄V) and Q=B(Es⁄V)+C, respectively. Here A, B and C are the constants depending upon the crystal structure and the chemical nature of the metal. The variations in the values of these constants are suggested to be due to the differences in (a) the nature of bonding between the constituent atoms and (b) the dependence of lattice vibration on the specific volume of the matrix.
