Atomic thermal vibrations of the light actinide elements

Conference · Fri Oct 01 04:00:00 EDT 1993

OSTI ID:10192567

Lawson, A C; Goldstone, J A; Cort, B; Sheldon, R I; Foltyn, E M

We have been using time-of-flight neutron powder diffraction to determine the Debye-Waller factors of the light actinide elements. The Debye-Waller factor is a measure of the mean-square atomic displacement that arises from the thermal motion of the atoms in any solid. Its temperature dependence determines a Debye-Waller temperature, {Theta}{sub DW}, that is characteristic of the elastic properties of the solid. The data are obtained by Rietveld analysis of neutron diffraction powder patterns obtained at several temperatures. We have analyzed the results for {alpha}-U, {alpha}-Np, {alpha}-Pu and {gamma}-Pu{sub 0.95}Al{sub 0.05}. The measured temperature dependence of the {Theta}{sub DW}`s can be interpreted with an ``effective`` Groneisen constant, whose numerical values are much too high to be explained with harmonic forces.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36; W-31109-ENG-38
• OSTI ID: 10192567
• Report Number(s): LA-UR--93-3464; CONF-930905--8; ON: DE94000684
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702
ALUMINIUM ADDITIONS
DEBYE-WALLER FACTOR
NEPTUNIUM-ALPHA
NEUTRON DIFFRACTION
PHYSICAL PROPERTIES
PLUTONIUM BASE ALLOYS
PLUTONIUM-ALPHA
PLUTONIUM-DELTA
PROPERTIES OF RADIOACTIVE MATERIALS
TEMPERATURE DEPENDENCE
URANIUM-ALPHA
VOLUME