Ｐｄ（１１１）表面における水素吸収・放出ダイナミクス

Abstract

Hydrogen absorption into the Pd (111) surface and desorption from the subsurface to the Pd (111) surface are investigated. In particular, the role of hydrogen-induced relaxation of the Pd lattice in absorption and desorption processes are studied. We performed the quantum dynamics calculations of H/Pd (111) absorption and desorption probabilities that include the surface atoms' motion using the time-independent coupled-channel method. Based on the calculation results for both the hydrogen absorption and desorption probabilities, we find that the hydrogen motion and the surface lattice relaxation are dynamically coupled. Depending on the hydrogen translational energy, the surface lattice motion either promotes or hinders the penetration of hydrogen into (desorption from) the surface (subsurface). Furthermore, the surface temperature dependence of hydrogen desorption dynamics is investigated. Based on the calculation results, we find that the hydrogen desorption is promoted by an increase in the surface temperature.