Quantum aspects of hydrogen motion in niobium at high temperatures

Abstract

The quantum aspects of H motion in Nb are elucidated using the path integral simulation technique. We argue that the most important effect around 500 K can be viewed as a temperature and isotope dependent shift of the potential energy surface, and that treating the dynamics of H motion classically at that temperature is reasonable. The purely classical isotope effect is also determined but our molecular dynamics simulation data do not exhibit the "classical" isotope effect for the prefactor, D0 ∝ msu-1 2, owing to the more complicated diffusion behavior at high temperatures. © 1995.