Reverse MÖssbauer effect as a possible source of “hot” protons in hydrogen absorbing metals

The “reverse Mössbauer effect” (RME) was recently proposed to explain some of anomalous dynamic behaviors of particles absorbed in crystalline solids. RME theory posits that a particle in non-equilibrium state with respect to a crystal, is scattered by the whole crystal with a momentum proportional to a vector representing a reciprocal lattice point. The scattering and the momentum transferable to the particle are expected to occur with a well-defined probability and a predictable distribution. As examples of application to hydrogen absorbing metals, we selected two different phenomena: the surprisingly easy manipulation of hydrogen absorbed in Pd by STM experiments at low temperature, and the anisotropy of hydrogen diffusion in Ni single crystals. We demonstrate that the RME can help in explaining the considered phenomena.