Effect of thermal vibration on low-energy collision cascades

Using computer simulation, collision sequences of energy up to 100 eV been studied in Cu at zero and room temp. The effect of correlated thermal vibration and zero point motion on the length of focused collision sequences, on the energy loss per collision, and on the radius of created Frenkel pairs has been evaluated. Collision sequences along close-packed atomic rows are found to exist for recoil energies well above the focusing energy; however, the length of the sequences is reduced by thermal vibration and zero point motion. A semi-empirical law which relates the energy loss per collision < 110 > direction with energy and temperature has been derived. Experimental results on the production of Frenkel pairs are discussed. 13 ref