X-ray determination of valence-electron charge density and its temperature dependence in indium antimonide

1976 ◽  
Vol 13 (6) ◽  
pp. 2479-2488 ◽  
Author(s):  
D. H. Bilderback ◽  
R. Colella
1986 ◽  
Vol 137 (2) ◽  
pp. 441-447 ◽  
Author(s):  
U. Pietsch ◽  
V. G. Tsirelson ◽  
R. P. Ozerov

1994 ◽  
Vol 364 ◽  
Author(s):  
S. Swaminathan ◽  
I. P. Jones ◽  
D. M. Maher ◽  
H. L. Fraser

AbstractIn recent years, the determination of x-ray structure factors and hence the electron charge density distribution in TiAl has received considerable attention. Experimental assessment of electron charge densities requires accurate values of the Debye-Waller (D-W) factors. This work attempts to determine the Debye-Waller factors from measurements of an Al rich off-stoichiometric single crystal of TiAl using the four circle x-ray diffraction method. The results suggest an ordered substitution of the excess Al atoms on the Ti-sublattice. This result is consistent with previous site occupancy studies.


2002 ◽  
Vol 209 (4-6) ◽  
pp. 273-277 ◽  
Author(s):  
F.N. Chukhovskii ◽  
D.V. Novikov ◽  
T. Hiort ◽  
G. Materlik

1991 ◽  
Vol 238 ◽  
Author(s):  
Genrich L. Krasko

ABSTRACTImpurities, such as H, P, S, B, etc, have a very low solubility in iron, and therefore prefer to segregate at the grain boundaries (GBs). In order to analyze the energetics of the impurities on the iron GB, the LMTO calculations were performed on a simple 8-atom supercel 1 emulating a typical (capped trigonal prism) GB environment. The so-called “environment-sensitive embedding energies” were calculated for H, B, C, N, O, Al, Si, P, and S, as a function of the electron charge density due to the host atoms at the impurity site. It was shown that, at the electron charge density typical of a GB, B and C have the lowest energy among the analyzed impurities, and thus would compete with them for the site on the GB, tending to push the other impurities off the GB. The above energies were then used in a modified Finnis-Sinclair embedded atom approach for calculating the equilibrium interplanar distances in the vicinity of a (111) σ3 tilt GB plane, both for the clean GB and that with an impurity. These distances were found to be oscillating, returning to the equilibrium spacing between (111) planes in bulk BCC iron by the 10th-12th plane off the GB plane. H, B, C, N and O actually dampen the deformation wave (making the oscillation amplitudes less than in the clean GB), while, Al, Si, P and S result in an increase of the oscillations. The effect of B, C, N and O may be interpreted as cohesion enhancement; this conclusion supports our earlier first-principles results [1] on B and C.


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