Anharmonicity of lattice vibrations in zinc by elastic neutron scattering

Abstract

The form of the effective anharmonic one-particle potential up to quartic terms is given and the expression of the temperature factor is derived for atoms occupying the sites of the point-group symmetry 6m2. The theory is applied to the analysis of the elastic thermal-neutron scattering data from a single crystal of Zn measured at 295 K and corrected for extinction and inelastic scattering contamination. The data show significant quartic terms. The values obtained for the anharmonic potential parameters correspond to the mean-square amplitudes (u 2) =0-0114 (3) A 2 and (u 2) =0.0257 (5) A 2 of the atomic vibrations in the principal directions. The present results are compared with other recent determinations. The discrepancy of the experimental values with theoretical calculations can be accounted for in full by constant-volume anharmonic effects.

Anharmonic thermal vibrations and the position parameter in wurtzite structures. I. Cadmium sulphide

“…The studies of anharmonicity in hexagonal structures include those of zinc (Albanese, Deriu & Ghezzi, 1976, Merisalo & Larsen, 1977Merisalo, J/irvinen & Kurittu, 1978;Kurki-Suonio, Merisalo & Peltonen, 1979;VahvaselkS., 1980), cadmium (Merisalo, Peljo & Soininen, 1978;Field, 1982), beryllium (Larsen, Lehmann & Merisalo, 1980) and Li3N (Zucker & Schulz, 1982). Nizzoli (1976) has discussed anharmonicity in h.c.p.…”

On antisymmetric atomic vibrations in zinc

“…In a previous paper (Merisalo & Larsen, 1977; hereinafter referred to as paper I) we reported the results and analysis of a neutron single-crystal diffraction study of Zn at 300 K. The data, interpreted in the framework of the effective one-particle potential approximation, showed significant quartic terms in the anharmonic potential, whereas the value of the cubic (antisymmetric) anharmonic parameter a33 representing deviations from axial symmetry in the initial analysis did not differ significantly from zero and was consequently ignored in the final refinement.…”

On anharmonicity in cadmium

“…The lattice constants given by Rossmanith (1978) The theory used in the analysis was that given by Merisalo & Larsen (1977) in their analysis of the hexagonal metal zinc. The one-particle potential appropriate to the site symmetry in A 3 structures is V(u) : V 0 "4-//2(0;20 K20 + fl00) + u3 a33 K33 "~-U4(0~40 K40 + ~20 K20 + Y00),…”