Lattice dynamics of. cap alpha. -uranium

Journal Article · Fri Jun 15 04:00:00 EDT 1979 · Phys. Rev., B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.19.6028· OSTI ID:6262268

Crummett, W P; Smith, H G; Nicklow, R M; Wakabayashi, N

The room-temperature lattice dynamics of ..cap alpha..-uranium has been investigated. The phonon dispersion curves along the orthorhombic high-symmetry directions have been measured using inelastic neutron scattering techniques. The dispersion curves in the (0zeta0) and (00zeta) directions are not very unusual. However, a depression and pronounced dips are observed in the (zeta00) direction. The slopes of the long-wavelength acoustic branches are in agreement with the slopes predicted from the elastic constants. A four-neighbor Born--von Karman general-tensor model, a 12-neighbor axially symmetric model, a simple shell model, and a simple Heine-Abarenkov pseudopotential model are unable to satisfactorily reproduce some of the (zeta00) branches. However, a modified form of the shell model which includes forces to six neighbors is found to reproduce most of the branches well, including those in the (zeta00) direction. A preliminary low-temperature experiment has revealed extra elastic scattering as well as significant phonon softening along the (zeta00) direction.

• Research Organization: Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• OSTI ID: 6262268
• Journal Information: Phys. Rev., B: Condens. Matter; (United States), Journal Name: Phys. Rev., B: Condens. Matter; (United States) Vol. 19:12; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ACTINIDES
COHERENT SCATTERING
DIFFRACTION
DISPERSION RELATIONS
ELASTIC SCATTERING
ELECTRONIC STRUCTURE
ELEMENTS
INELASTIC SCATTERING
METALS
NEUTRON DIFFRACTION
PHONONS
QUASI PARTICLES
SCATTERING
URANIUM
URANIUM-ALPHA