Calculation of Thermodynamic, Electronic, and Optical Properties of Monoclinic Mg2NiH4

TitleCalculation of Thermodynamic, Electronic, and Optical Properties of Monoclinic Mg2NiH4
Publication TypeJournal Article
Year of Publication2002
AuthorsWhittier R Myers, Lin-Wang Wang, Thomas J Richardson, Michael D Rubin
JournalJournal of Applied Physics
Volume91
4879
Issue8
Pagination4879-4885
Date Published04/2002
Abstract

Ab initio total-energy density functional theory is used to investigate the low temperature (LT) monoclinic form of Mg2NiH4. The calculated minimum energy geometry of LT Mg2NiH4 is close to that determined from neutron diffraction data, and the NiH4 complex is close to a regular tetrahedron. The enthalpies of the phase change to high temperature (HT) pseudo-cubic Mg2NiH4 and of hydrogen absorption by Mg2Ni are calculated and compared with experimental values. LT Mg2NiH4 is found to be a semiconductor with an indirect band gap of 1.4 eV. The optical dielectric function of LT Mg2NiH4 differs somewhat from that of the HT phase. A calculated thin film transmittance spectrum is consistent with an experimental spectrum.

DOI10.1063/1.1454206
LBNL Report Number

LBNL-47519