TY - JOUR T1 - Calculation of Thermodynamic, Electronic, and Optical Properties of Monoclinic Mg2NiH4 JF - Journal of Applied Physics Y1 - 2002/04// SP - 4879 EP - 4885 A1 - Whittier R. Myers A1 - Lin-Wang Wang A1 - Thomas J. Richardson A1 - Michael D. Rubin AB - 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. VL - 91 IS - 8 U1 -

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U2 - LBNL-47519 DO - 10.1063/1.1454206 ER -