engleski

THE ELECTRONIC STRUCTURE OF THE YNi5, YNi4Al AND YNi3Al2 INTERMETALLIC COMPOUNDS AND THEIR MODEL MONOHYDRIDES

The electronic structure of the YNi5, YNi4Al and YNi3Al2 intermetallic compounds and their model monohydrides was calculated using the tight-binding version of the linear muffin-tin orbital method within the atomic sphere approximation (TB-LMTO-ASA). The total densities of states and the contribution of particular atomic states were used to discuss the modification of the electronic structure upon substitution of nickel by aluminium, as well as to discuss the features of metal-hydrogen bonding in the model monohydrides. It was found that replacement of nickel by aluminium expands the range of filled states in the intermetallic compounds, while the unfilled states which are dominated by contribution of 4d-states of yttrium are getting closer to the Fermi level. In the model monohydrides YNi5H, YNi4AlH and YNi3Al2H all densities of states exhibit a characteristic metal-hydrogen bonding structure. This bonding structure is shifted to lower energies as the aluminium content increases. Aluminium atoms contribute more to the metal-hydrogen bonding structure than the nickel atoms when placed at the same crystallographic positions.

Rare earth intermetallics; Hydrogen absorbing materials; Electronic structure

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