Neutron diffraction investigations of thermal atomic displacements in Ta and Ag

The neutron powder diffraction technique has been used to determine the atomic thermal displacements in Ag and Ta at room temperature. The data were analyzed by the Rietveld profile refinement procedure. The thermal parameters obtained were corrected for the contributions of absorption and thermal diffuse scattering. The Debye-Waller factors were 0.31 (1) and 0.84 (2) Å² for tantalum and silver, respectively. The thermal parameters were also determined from the conventional independent integrated intensities. The atomic thermal displacements derived by the two methods do not differ significantly.