Thermal vibration and melting from a local perspective

Stern, E. A.; Livns, P; Zhang, Z

doi:10.1103/physrevb.43.8850

Cited by 213 publications

(179 citation statements)

References 15 publications

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“…For weak thermal disorder, the temperature dependence of the lowest-order cumulants can be expressed in terms of the force constants of the pair potential (6). In Dalba & Fornasini (1997), the classical approximation of Tranquada & Ingalls (1983) and Stern et al (1991) has been reported.…”

Section: Pair Potential Energymentioning

confidence: 93%

On EXAFS Debye-Waller factor and recent advances

2015

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The effects of structural and vibrational disorder on the EXAFS signals are parameterized in terms of the Debye Waller (DW) factor. Here the vibrational contribution is addressed, which for most systems can be singled out by studying the temperature dependence of the EXAFS DW factor, which corresponds to a good accuracy to the parallel mean square relative displacement (MSRD) around the inter-atomic equilibrium distance. By comparing the first-shell EXAFS thermal expansion with the crystallographic thermal expansion one can evaluate the perpendicular MSRD. The results of recent measurements on copper and on several tetrahedral semiconductors are here critically compared and some properties of the MSRDs are discussed, such as the dependence of correlation, force constants and vibrational anisotropy on crystal structure and bond ionicity as well as the relative merits of the correlated Debye and Einstein models. The anharmonic contribution to the parallel MSRD of CdTe has been evaluated and a quasi-harmonic analysis has been attempted, leading to an estimation of the bond Grü neisen parameter.

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Section: Pair Potential Energymentioning

confidence: 93%

On EXAFS Debye-Waller factor and recent advances

2015

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“…The best fit values of 2 0 S were found to be 0.873 (14) and 0.947 (19), respectively. In order to break the correlation between the amplitude factors in the fit, the 2 0 S parameter of the NPG was fixed to that of bulk Au (0.873).…”

Section: Data Processing and Analysismentioning

confidence: 94%

“…19,20 In the next Section we present experimental details on synthesis, scanning electron microscopy characterization and EXAFS measurements of NPG. Section III describes the data processing and analysis.…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of nanoporous gold

et al. 2012

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We measured the thermal expansion coefficient and Debye temperature of nanoporous gold (NPG) using Extended X-ray Absorption Fine Structure technique. Reduction of the nearest neighbor distances in NPG by ca. 0.01 Å compared to the bulk gold was attributed to the surface tension caused, in turn, by the finite size effect of the NPG ligaments. We also obtained that the Debye temperature in NPG is 5% lower than in bulk gold. We interpreted these observations in the framework of a bimodal distribution of surface and bulk bonds with different values of Debye temperature. The surface bonds with low Debye temperature extend within ca. 4 layers of Au atoms located on the pore surface, in a good agreement with prior resistivity measurements and theoretical predictions. 63.22.Dc, 61.05.cj, 65.40.De, PACS number(s):

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“…19 In another study, ∆σ 2 of lead increases linearly with temperature (10 -4 Å 2 /K) up to the melting temperature. 41 The Debye-Waller factor for large clusters should be chosen lower than for smaller clusters, because the structural disorder is lower. We have shown that it is important to measure series of catalysts, so that trends can be identified.…”

Section: Fitting Exafs Data Collected At Elevated Temperaturesmentioning

confidence: 99%

Analysis of in situ EXAFS data of supported metal catalysts using the third and fourth cumulant

Bus

Miller²,

Kropf

et al. 2006

Phys. Chem. Chem. Phys.

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[DO NOT ALTER/DELETE THIS TEXT]X-ray absorption spectra of supported Pt catalysts with various Pt cluster sizes were collected between 77 and 673 K, in inert and hydrogen atmospheres. When analyzing these spectra with the standard EXAFS equation a Pt-Pt bond contraction and a large increase in the inner potential correction were observed with increasing temperature.These errors are up to 0.08 Å and 10 eV for clusters of 1 nm in diameter. They were corrected by including the third and fourth cumulants as fit parameters. Fit guidelines were developed to analyze EXAFS data of supported metal catalysts collected at elevated temperatures, allowing for asymmetry and broadening or sharpening of the pair distribution function. These comprise fixing fit parameters, using different k-weightings, and identifying trends in series of experiments. By fitting the EXAFS spectra using these guidelines, it was determined that in small Pt clusters the Pt-Pt bond is 0.10 Å shorter than in bulk Pt. These contracted bonds relax to distances near that of bulk Pt upon hydrogen chemisorption.2

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Thermal vibration and melting from a local perspective

Cited by 213 publications

References 15 publications

On EXAFS Debye-Waller factor and recent advances

On EXAFS Debye-Waller factor and recent advances

Thermal properties of nanoporous gold

Analysis of in situ EXAFS data of supported metal catalysts using the third and fourth cumulant

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