ON THE VALENCE HYPERFINE FIELD OF ATOMS IN FACE-CENTERED-CUBIC IRON AND NICKEL-CONTAINING 2P INTERSTITIALS

The valence hyperfine fields of atoms in fee iron and nickel containin g 2p interstitials X (X = B, C, N, O and F) have been investigated by applying the spin-polarized LMTO method. The results on the valence hy perfine field and the hyperfine coupling constants indicate that the F e-Fe and Ni-Ni interactions are sensitively dependent on which interst itial atom is present, and also that Fe-X interactions dominated by bo nding states are distinguishable from those between Ni and X atoms whi ch 'prefer' anti-bonding states. The volume (distance) dependences of the valence hyperfine fields in Fe-X are also investigated, and the re sults reveal an anomalous distance dependence of the three hyperfine c oupling constants. It is concluded that it is the unusual distance dep endence of the strong interactions between face-centred Fe and X atoms that gives rise to these anomalies.