Debye-Waller Parameter Research Articles

The Debye–Waller factor of KBr by powder elastic neutron diffraction

The Debye-Waller parameter B of KBr has been determined by triple-axis neutron diffraction with a powder sample. Calculations have also been made to find the contributions of TDS to the diffraction peaks obtained by this technique and they were found to be negligible as expected. The B value thus found is 2.33 ± 0.09 A2.

On the dependence of X-ray Debye–Waller parameters on atomic form factors

An analysis of powdered-diamond diffraction data with Hartree-Fock and standard molecular C atomic form factors yields the Debye-Waller parameters 0.20 ± 0.01 and 0.172 ± 0.009 Å2 respectively. The lattice-dynamic value, which is calculated here from published phonon dispersion curves measured by inelastic neutron scattering, is 0.149-0.150 Å2 at 298°K. It is shown that a small amount of an orbital product, χSCF1s χSTO2s, in the core atomic scattering factor can dramatically alter the Debye-Waller parameter. For diamond, this latter scattering factor gives a value of 0.134 ± 0.009 Å2.

Charge density study of diamond

Generalized x-ray scattering factors are applied to published x-ray powder measurements of diamond for a charge density analysis. The Debye-Waller parameter (0.140±004A2) is substantially lower than published results based on the Hartree-Fock atomic scattering factor (.206±.003A2). The electron content in the atomic octapole and hexadecapole electron density moments are in agreement with other analyses. The contribution of the valence electron density to the gradient of the electric field gradient is 〈Vxyz〉= 1.5± 0.2× 1032joules m −3 coul −1. The components, from a similar contribution, of the gradient of the gradient of the electric field gradient are 〈Vα α α α〉= 5.3± 1.5× 1042 J m−4· C−1 and 〈Vα α β β〉= −(1/2)〈Vα α α α〉. The analysis also has provided some guide lines for the application of generalized x-ray scattering factors to organic molecular crystals.

Debye-Waller factor and Debye temperature for Fe, Mo, Ta, and W

The Debye-Waller parameter and the Debye temperature for iron, molybdenum, tantalum, and tungsten have been calculated from general force constant models. Comparison of the x-ray Debye temperatures with the heat capacity Debye temperatures is made and discussed.