Multi-phonon scattering and Ti-induced hydrogen dynamics in sodium alanate

We use ab initio methods and neutron inelastic scattering (NIS) to study the structure, energetics, and dynamics of pure and Ti-doped sodium alanate (NaAlH_4), focusing on the possibility of substitutional Ti doping. The NIS spectrum is found to exhibit surprisingly strong and sharp two-phonon features. The calculations reveal that substitutional Ti doping is energetically possible. Ti prefers to substitute for Na and is a powerful hydrogen attractor that facilitates multiple Al--H bond breaking. Our results hint at new ways of improving the hydrogen dynamics and storage capacity of the alanates.Comment: 5 pages, with 4 postscript figures embedded. Uses REVTEX4 and graphicx macro

Molecular structure of diantipyrylphenylmethane and its complex with neodymium nitrate

The structures of diantipyrylphenylmethane (DAPM) and its complex with neodymium nitrate [Nd(NO3)3 · DAPM · CH3OH] · 2CH3OH are determined by X-ray diffraction. The free ligand adopts a trans conformation with the opposite orientation of the oxygen atoms of the carbonyl groups. In the complex, diantipyrylphenylmethane acts as a bidentate ligand and coordinates the Nd atom through the carbonyl oxygen atoms, thus forming the eight-membered metallocycle. The coordination number of neodymium is nine (six O atoms of the bidentate nitrate groups, two O atoms of diantipyrylphenylmethane, and one O atom of the methanol molecule). © 2002 MAIK "Nauka/Interperiodica"