ALLOYING EFFECTS ON THE ELECTRONIC-STRUCTURE OF ZRMN2 INTERMETALLIC HYDRIDE

The electronic structures of ZrMn2 intermetallic hydride containing a variety of alloying elements are investigated by the DV-X alpha cluste r method. It is found that hydrogen atom makes a strong chemical bond with Mn atoms rather than Zr atoms in pure ZrMn2 hydride. The substitu tion of alloying elements for Mn atoms scarcely modifies the total bon d strength between hydrogen and metal atoms, despite the fact that hyd rogen absorption and desorption characteristics change significantly w ith alloying elements. On the contrary, both the Mn-Mn and the Zr-Mn i nteractions are greatly affected by alloying. It is shown that the rat io of the Zr-Mn bond order to the Mn-Mn bond order in a small tetrahed ron containing a hydrogen atom, correlates well with experimental data of the equilibrium hydrogen pressure of alloyed ZrMn2. (C) 1998 Elsev ier Science S.A. All rights reserved.