Atomic and electronic structures of hydrogenated rare-earth glasses

众所周知，稀土(RE)-过渡金属(TM)-简单金属(SM)系统在很宽的成分范围内很容易形成玻璃合金，并且对氢非常敏感。用X射线衍射、X射线光电子能谱和热脱附谱研究了La-Ni-Mg(Al)和Nd-Fe-B合金玻璃及其氢化物的原子、电子结构和表面态。在所有这些系统中，玻璃结构由金属原子的随机堆积组成，但RE-TM相互作用得到加强。氢化作用通过形成强的RE-H化学键改变了无序结构，打破了RE-TM键，导致金属原子的微观聚集。原子结构的径向分布分析和光电子能谱、核能级和价带光谱一致地观察到了这一效应，氢气在玻璃中的储存率为H/M=1.0-1.7。详细研究了它们的吸放氢性能。具体地说，La_5Ni_(40)；Mg_(55)合金玻璃作为储氢材料是有利的。这些研究已经在定期论文中发表，并将在国际研讨会上发表。

It is well known that rare-earth (RE) -transition metal (TM)- simple metal (SM) systems readily form glassy alloys over wide composition ranges and are very reactive to hydrogen. In this research, atomic and electronic structures and surface states of La-Ni-Mg(Al) and Nd-Fe-B alloy glasses and their hydrides have been studied by means of X-ray diffraction, X-ray photoemission spectroscopy and thermal desorption spectrometry. In all these systems the glass structures consist of random packing of the metal atoms, where however RE-TM interaction is strengthened. Hydrogenation alters the random structures by forming strong RE-H chemical bonds, which break the RE-TM bonds and cause micro-clustering of metal atoms. This effect was observed by radial distribution analysis of atomic structure and photoemission core-level and valence-band spectra consistently.Hydrogen can be stored in these glasses by H/M=1.0-1.7 depending on the compositions. Their hydrogen absorption-desorption properties have been studied in detail. Specifically, La_5Ni_<40>Mg_<55> alloy glass is found to be profitable for use as a hydrogen storage material.These studies have been published in regular papers and are going to be presented at international symposiums.