Mechanism of Stabilization of the β Phase of Vanadium-Hydrogen System

Abstract

A formulation for the elastic energy of metal-hydrogen systems is derived by taking account of uniaxial components of strain in addition to dilatation, and a change of the self-trapped state with elongation of the c axis is examined by solving the Schrödinger equation for a hydrogen isotope on interstitial sites in a bct lattice. From these calculations, it is shown that, in VH_0.5 and VD_0.5, the bct structure with an axial ratio c⁄a=1.1 is stabilized at low temperatures, with H(D) atoms occupying O_z sites.