Hi there~ I have some questions about hydrogen storage alloys. (TiFe, ZrV2, LaNi5, Mg2Ni, etc.) As far as I know, the hydrogen sorption precesses are as following: Hydrogen molecules "physically" absorbed on the surface of alloy which is called alpha-phase. Hydrogen molecules become hydrogen atoms. Hydrogen atoms diffuse into crystal lattice of alloy which is called beta-phase. And the desorption processes are just the opposite. My questions are: What is the driving force for the hydrogen molecules to split into hydrogen atoms? Also, what is the driving force that makes hydrogen atoms diffuse into crystal lattice of alloy. For thedesorption processes: What makes hydrogen atoms diffuse to the surface of alloy? And what makes the hydrogen atoms become hydrogen molecules? These questions have troubled me for a long time. Thank you in advance for your kindly responses!