It was shown that a correlation existed between the Gibb’s activation energy for diffusion, and the melting point. Calculations for Na suggested that there was a linear relationship between the 2 quantities. The present approach was also capable of predicting the activation volume as a function of pressure. The activation volume at 364.45K, as calculated for Na under zero pressure, was equal to 12.63cm3/mol. This was higher than the volume which had been reported for a temperature of 288K and zero pressure. The activation volume thus increased with temperature. Furthermore, it was found to decrease with increasing pressure. It was concluded that the activation volume variation was responsible for the curvature of Arrhenius plots.

P.Kuchhal, R.Kumar, N.Dass: Materials Science Forum, 1996, 223-224, 199-204