This question is of increasing relevance as modeling of materials processes based on atomistic input is carried further. Several studies have shown that harmonic transition state theory is often applicable even at rather high temperatures. Dislocation processes, on the other hand, are of a different nature.
Dislocations are extended line defects and their motion involve the collective motion of many atoms.
It is therefore from the outset less clear whether anharmonic entropic effects or dynamical recrossings may give rise to strongly temperature dependent prefactors. In the present study we investigate the annihilation of a screw dislocation dipole by cross slip in copper, using both molecular dynamics simulations and rate theory, and show that the obtained activation energies agree completely. Also, the rate-prefactor for cross slip determined from the MD simulations is found to have a typical atomistic value, in agreement with a theoretical estimate. The two determining factors in the dislocation density of deformed metals are the dislocation multiplication and annihilation rates. At ambient temperature, where climb processes are limited, dislocation annihilation occurs only via cross slip of screw dislocations.