Metal-hydrogen binding energy

The problem of hydrogen storage in metals is related with the problem of determination of hydrogen binding energy and diffusion constants in the metals. 

We have developed equipment, which allows obtaining information on the material structure from the hydrogen extraction curve in heating of a probe in vacuum. Accurate determination of the extraction curve provides information both on the hydrogen binding energy in metal and on concentration of spatial microtraps. 

The solution phase is modeled explicitly by the sequential addition of solution molecules in order to completely fill the vacuum region that separates repeated metal slabs (Fig. 4.2a) up to the known density of the solution. The inclusion of explicit solvent molecules allow us to directly follow the influence of specific intermolecular interactions (e.g., hydrogen bonding in aqueous systems or electron polarization of the metal surface) that influence the binding energies of different intermediates and the reaction energies and activation barriers for specific elementary steps. 

In addition to the observed polarization transfer, attachment of the hydrogenated product to the catalyst - most likely in the form of a re-complex between the aromatic portion of a product and the cationic catalyst - has also been observed in the 13C-PHIP-NMR spectra. The associated larger shift range of the affected 13C will make it possible to characterize the nature of this attachment as well as the associated binding energies of the hydrogenation product to the catalysts metal center more precisely and effectively. 

The complexation of protonated amines, RNHJ, by crown ethers differs in many aspects from the complexation of metal cations. Whereas complexes with metal cations derive their binding energy mainly from electrostatic forces, complexes with ammonium ions are likely also to be stabilized by hydrogen... 

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