Eur. Phys. J. B 82, 1-6 (2011)
https://doi.org/10.1140/epjb/e2011-10916-5

Theoretical investigation of the hydrogenation induced atomic rearrangements in palladium rich intermetallic compounds MPd₃ (M = Mg, In, Tl)

Department of Chemistry, University of Saarland, 66123 Saarbrücken, Germany

Corresponding author: ^a m.springborg@mx.uni-saarland.de

Received: 23 November 2010
Revised: 12 April 2011
Published online: 29 June 2011

Abstract

Based on results from density-functional calculations we present an interesting and unusual mechanism for a structural change in a certain class of intermetallic compounds that can be induced through hydrogen absorption. Through an atomic rearrangement, palladium-rich intermetallic compounds MPd₃ (M = Mg, In, Tl) can change the structure from a tetragonal ZrAl₃ or TiAl₃ type to a cubic AuCu₃ type structure. Within the density-functional calculations we study a possible reaction pathway via a gliding of atomic layers with and without the presence of hydrogen. Subsequently, we argue that H-Pd interactions can be held responsible for the structural change upon hydrogen uptake, and that entropic and packing effects can explain the existence of the lower-symmetric structures in the absence of hydrogen.