YNi and its hydrides: Phase stabilities, electronic structures and chemical bonding properties from first principles

• Published in: Chemical physics Vol. 377; no. 1; pp. 109 - 114
• Main Authors: Matar, S.F., Nakhl, M., Al Alam, A.F., Ouaini, N., Chevalier, B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25-11-2010; Elsevier
• Subjects: ASW; Chemical bonding; Chemical Sciences; CrB-type; DFT; Equation of state; FeB-type; GGA; Hydrides; Material chemistry; VASP; GGA; VASP; CrB-type; DFT; ASW; Hydrides; Chemical bonding; FeB-type; Equation of state
• ISSN: 0301-0104
• DOI: 10.1016/j.chemphys.2010.08.022

Base centered orthorhombic YNiH
X
structure. For
x
=
3, only H1 and H2 are present. Highest hydrogen content YNiH
4 is obtained when H3 are added.
Within density functional theory, establishing the equations of states of YNi in two different controversial structures in the literature, leads to determine the orthorhombic FeB-type as the ground state one with small energy difference. For YNiH
3 and YNiH
4 hydrides crystallizing in the orthorhombic CrB-type structure the geometry optimization and the ab initio determination of the H atomic positions show that the stability of hydrogen decreases from the tri- to the tetra- hydride. New states brought by hydrogen within the valence band lead to its broadening and to enhanced localization of metal density of states. The chemical bonding analysis shows a preferential Ni–H bonding versus Y–H.