Inelastic neutron scattering metal hydrides

CCD = charge-coupled device IHIs = interligand hypervalent interactions ILL = Institut Lane-Langevin INS = inelastic neutron scattering IPNS = intense pulsed neutron source LINAC = linear accelerator MaNDi=macro-molecular neutron diffractometer NiMH=nickel-metal OPAL = open pool Australian light-water reactor hydride SANS = small-angle neutron scattering SNS = spallation neutron source. 

G. Auffermann, G. Barrera, D. Colognesi, G. Corradi, A.J. Ramirez-Cuesta M. Zoppi (2004). J. Phys. C Condens. Matter, 16, 5731-5743. Hydrogen dynamics in heavy alkali metal hydrides obtained through inelastic neutron scattering. 

The study of amorphous metal-hydrogen systems has started quite recently in contrast to the vast amount of work on the properties of crystalline metal-hydrogen systems that dates back over several decades and makes use of a great number of different techniques. The amorphous system a - Tij CuyHx has been studied by Inelastic Neutron Scattering (INS)" and Nuclear Magnetic Resonance (NMR) Very recently an extensive study of the structure of CuTi amorphous alloys and hydrides has been made by neutron diffraction and computer simulation (ref, 4 and references therein). 

A review is presented of some recent applications of neutron vibrational spectroscopy to the study of disordered metal-hydrogen systems. The examples discussed cover a range of systems from simple dilute solutions in bcc or fee metals to amorphous alloy hydrides. It is shown that neutron inelastic scattering studies of the vibrational density of states provide a powerful and sensitive probe of the local potentials and bonding sites of hydrogen in metals and often reveal critical information on the novel microscopic physical properties and behavior of disordered metals-hydrogen systems, including those influenced by interstitial or substitutional defects. 

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