Lattice dynamics and intrinsic phonon broadening in the alloy Cu0.92Ge0.08

1988 ◽  
Vol 66 (8) ◽  
pp. 724-733
Author(s):  
E. D. Hallman ◽  
E. C. Svensson
Keyword(s):  
Force Constant ◽  
Pure Copper ◽  
Waller Factor ◽  
Force Constants ◽  
Transition Elements ◽  
Disorder Effects ◽  
Dilute Alloys ◽  
Debye Waller Factor ◽  
First Time ◽  
Constituent Atom

Using inelastic scattering of slow neutrons, we have determined the phonon frequencies and intrinsic line widths for the dilute face-centred cubic alloy Cu0.92Ge0.08 (Cu(Ge)) at 296 K. A limited number of measurements have also been made at 96 and 500 K. Spectrometer resolution calculations, using actual instrument and specimen parameters, have been performed and intrinsic phonon widths have been obtained by deconvolution from observed widths. The phonons in Cu(Ge) are well defined and similar to those for copper. Real contributions of the force-constant disorder in the alloy to intrinsic phonon widths are seen. To our knowledge, this is the first time that such effects have been conclusively observed for such dilute alloys. Constituent-atom mass differences are small for this alloy, and no mass disorder effects have been observed. Born–von Kármán model force-constant fits to the frequency data at 296 K are presented and compared with a model for pure copper. The frequency distribution and other thermal data, including the temperature dependence of the specific heat, the Debye–Waller factor, and the Debye temperature, are also given. The Cu(Ge) force constants are compared with those for 14 other iron-group transition elements and alloys. Systematic trends in the force constants as a function of 3d + 4s electron concentration are apparent.

VHF Plasma CVD Synthesis of Photochromic ZnO Nanoparticle

MRS Advances ◽  
2019 ◽  
Vol 4 (27) ◽  
pp. 1573-1577
Author(s):  
Hiroshi Kajiyama ◽  
Shin Kuboyama ◽  
Atsushi Otomo ◽  
Hiroki Uyama ◽  
Toshihiro Matsuura ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Zno Nanoparticles ◽  
Density Functional ◽  
Waller Factor ◽  
Threshold Temperature ◽  
Zno Nanoparticle ◽  
Functional Theory ◽  
Debye Waller Factor ◽  
Zno Crystal ◽  
First Time

AbstractPhotochromic (PC) ZnO nanoparticles are synthesized for the first time by using a VHF plasma enhanced CVD apparatus. The prepared ZnO film changes from transparent to PC state under UV irradiation; on being subjected to heat treatment, it changes back to transparent state. There is a threshold temperature for attaining the PC phase. The Debye-Waller factor of Zn atoms is specifically large for the PC ZnO. The ZnO nanoparticles contain carbon as impurity. The effects of C-O bonds on the ZnO crystal structure and density of states (DOS) are simulated based on density-functional theory. The results reveal that the crystal structure is slightly distorted and a sufficient DOS for PC light absorption is formed in the band gap.

Lattice Dynamics of Molybdenum and Chromium

1980 ◽  
Vol 35 (2) ◽  
pp. 230-235
Author(s):  
B. P. Singh ◽  
L. P. Pathak ◽  
M. P. Hemkar
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Lattice Dynamics ◽  
Waller Factor ◽  
Mean Square ◽  
Frequency Wave ◽  
Debye Waller Factor ◽  
Nearest Neighbours ◽  
The Mean ◽  
First Time

Abstract The frequency-wave vector dispersion relations, the frequency spectrum, the Debye temperature, the temperature dependence of the Debye-Waller factor and the mean square displacements of the atoms molybdenum and chromium, the metals for which long range forces are also important, have been computed on the basis of the extended improved Fielek model for BCC transition metals. The model considers, for the first time the d shell-d shell central interactions upto next-nearest-neighbours. The calculated results show a satisfactory agreement with the available experimental data.

The effect of temperature on high-resolution TEM image contrast

1995 ◽  
Vol 53 ◽  
pp. 640-641
Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz
Keyword(s):  
Form Factor ◽  
Inelastic Scattering ◽  
Accurate Method ◽  
Waller Factor ◽  
Effect Of Temperature ◽  
Specimen Thickness ◽  
Influence Of Temperature ◽  
Debye Waller Factor ◽  
Influence Of Temperature On ◽  
Atomic Form Factor

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).

Bonded Force Constant Derivation of Lysine-Arginine Cross-linked Advanced Glycation End-Products

2018 ◽  
Author(s):  
Anthony Nash ◽  
Nora H de Leeuw ◽  
Helen L Birch
Keyword(s):  
Molecular Dynamics ◽  
Force Constant ◽  
Computational Study ◽  
Force Constants ◽  
Quantum Mechanical ◽  
Advanced Glycation ◽  
Partial Charges ◽  
Cross Links ◽  
Complete Set ◽  
Dynamics Simulations

<div> <div> <div> <p>The computational study of advanced glycation end-product cross- links remains largely unexplored given the limited availability of bonded force constants and equilibrium values for molecular dynamics force fields. In this article, we present the bonded force constants, atomic partial charges and equilibrium values of the arginine-lysine cross-links DOGDIC, GODIC and MODIC. The Hessian was derived from a series of <i>ab initio</i> quantum mechanical electronic structure calculations and from which a complete set of force constant and equilibrium values were generated using our publicly available software, ForceGen. Short <i>in vacuo</i> molecular dynamics simulations were performed to validate their implementation against quantum mechanical frequency calculations. </p> </div> </div> </div>

RAMAN SPECTRA OF TITANIUM DI-, TRI-, AND TETRA-CHLORIDES

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3865-3868 ◽  
Author(s):  
H. MIYAOKA ◽  
T. KUZE ◽  
H. SANO ◽  
H. MORI ◽  
G. MIZUTANI ◽  
...  
Keyword(s):  
Force Constant ◽  
Raman Spectra ◽  
Normal Mode ◽  
Raman Band ◽  
Normal Mode Analysis ◽  
Force Constants ◽  
Mode Analysis ◽  
Oxidation Number

We have obtained the Raman spectra of TiCl n (n= 2, 3, and 4). Assignments of the observed Raman bands were made by a normal mode analysis. The force constants were determined from the observed Raman band frequencies. We have found that the Ti-Cl stretching force constant increases as the oxidation number of the Ti species increases.

Anharmonic contributions to the Debye-Waller factor of aluminium

1989 ◽  
Vol 72 (11) ◽  
pp. 1135-1140 ◽  
Author(s):  
R.C. Shukla ◽  
H. Hübschle
Keyword(s):  
Waller Factor ◽  
Debye Waller Factor

On the Debye-Waller factor in atom-surface scattering

1982 ◽  
Vol 45 (2) ◽  
pp. 287-298 ◽  
Author(s):  
N. Garcia ◽  
A. A. Maradudin ◽  
V. Celli
Keyword(s):  
Waller Factor ◽  
Surface Scattering ◽  
Debye Waller Factor
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