Effective Temperature Dynamics of Radiation Induced Amorphization

Materials exposed to radiation suffer structural changes over time. Typically, after exposure to radiation, a crystal will gradually lose its periodic structure and become amorphous. A theory of radiation amorphization should provide a description of the structural evolution. We study radiation amorphization in a simple molecular dynamics model and show that one can describe the amorphous steady-state using a structural effective temperature (different from the thermal bath temperature). We derive a theory that predicts the value of the steady-state effective-temperature as a function of the thermal bath temperature for a constant intensity of radiation. The theory agrees well with simulations results.