01573nas a2200241 4500008004100000245009300041210006900134260002400203520077100227653001000998653003101008653001101039653001501050653002201065100002001087700002601107700002701133700002401160700002101184700002501205700002301230856007801253 2002 eng d00aStructural and Electronic Properties of Magnesium-3D Transition Metal Switchable Mirrors0 aStructural and Electronic Properties of Magnesium3D Transition M aGolden, COc12/20023 a
We have observed reversible mirror-to-transparent state switching in a variety of mixed metal thin films containing magnesium and first-row transition elements including Ni, Fe, Co, Mn, and Ti. The very large changes in both reflectance and transmittance on loading these films with hydrogen are accompanied by significant structural and electronic transformations. The valence states and coordination of metal atoms during hydrogen loading were followed using dynamic in situ transmissionmode X-ray absorption spectroscopy. Time-resolved Mg K-edge and Ni, Co, Mn, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. These spectra are compared to those of reference materials and to predictions from calculations.
10aEXAFS10aHydrogen storage materials10aNEXAFS10athin films10ax-ray diffraction1 aFarangis, Baker1 aNachimuthu, Ponnusamy1 aRichardson, Thomas, J.1 aSlack, Jonathan, L.1 aMeyer, Bruno, K.1 aPerera, Rupert, C.C.1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/structural-and-electronic-properties01599nas a2200265 4500008004100000245008300041210006900124260001200193300001200205490001200217520077700229653001001006653003101016653001101047653001501058653002201073100002701095700002001122700002401142700002601166700002501192700002201217700002301239856007101262 2002 eng d00aX-Ray Absorption Spectroscopy of Transition Metal-Magnesium Hydride Thin Films0 aXRay Absorption Spectroscopy of Transition MetalMagnesium Hydrid c08/2003 a204-2070 v356-3573 aMixed metal thin films containing magnesium and a first-row transition element exhibit very large changes in both reflectance and transmittance on exposure to hydrogen gas. Changes in electronic structure and coordination of the magnesium and transition metal atoms during hydrogen absorption were studied using dynamic in situ transmission mode X-ray absorption spectroscopy. Mg K-edge and Ni, Co, and Ti L-edge spectra reflect both reversible and irreversible changes in the metal environments. A significant shift in the nickel L absorption edge shows it to be an active participant in hydride formation. The effect on cobalt and titanium is much less dramatic, suggesting that these metals act primarily as catalysts for formation of magnesium hydride.
10aEXAFS10aHydrogen storage materials10aNEXAFS10athin films10ax-ray diffraction1 aRichardson, Thomas, J.1 aFarangis, Baker1 aSlack, Jonathan, L.1 aNachimuthu, Ponnusamy1 aPerera, Rupert, C.C.1 aTamura, Nobumichi1 aRubin, Michael, D. uhttps://facades.lbl.gov/publications/x-ray-absorption-spectroscopy