Effect of point defects on graphite lattice parameters

Contributions of interstitial atoms and vacancies into graphite lattice parameter change along c and a axes are calculated on the basis on the binding order model (dependence of the carbon interatomic distance on the binding order is used). The contribution into graphite lattice parameter change from the aggregate of interstitial atoms: binary, ternary and larger ones up to extraplanes, is determined on the basis of the same model. The Δc/c : Δa/a ratio for irradiated graphite depending on the radiation and annealing temperature is analysed. Quantitatively calculated values of this ratio for the definite defects agree with the experiment