The model used to evaluate the single interstitial migration energy from property changes due to interstitials was extended to account for vacancy contributions. The annealing function obtained could be used to determine the relative contributions of the defects and was sufficiently sensitive to distinguish vacancy effects that were an order of magnitude less than interstitial effects. Application of the model to stored energy and thermal resistivity data yields the same values of the activation energy and temperature independent term obtained from c-axis and macroscopic length expansion rates. The results indicate that the stored energy associated with the di-interstitial was at least ten times greater than the stored energy associated with the vacancy. The minor role of vacancies in phonon scattering was discussed. The annealing function obtained from electrical resistivity changes in irradiated graphite was explained by assuming that the ratio of charge-carriers to scattering centers varies with irradiation temperatures below 55C. Above this temperature the changes were attributed to equal contributions from vacancies and interstitials.

Determination of the Single Interstitial Migration Energy from Stored Energy and Thermal Resistivity Changes in Irradiated Graphite. Schweitzer, D.G.: Carbon, 1965, 2[4], 407-12