Investigation of the anharmonic EXAFS oscillation of distorted HCP crystals based on extending quantum anharmonic correlated Einstein model

Tien, Tong Sy

doi:10.35848/1347-4065/ac21b3

Cited by 9 publications

(5 citation statements)

References 69 publications

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“…24 in which the Debye and Einstein temperatures are fitted to the data. Here we compare with an extended quantum anharmonic correlated Einstein (EQACE) model (Tien, 2021) and with Beni-Platzmann theory (Beni & Platzman, 1976) which treat the vibrational density of states (VDOS) as a delta function at the Einstein frequency, and as a polynomial with a cut-off at the Debye frequency, respectively. We modify the classical anharmonic correlated Einstein (CACE) model which tends to 0 at 0 K, by adding in quadrature a static offset term, from 2 at 10 K. We see good agreement with both the EQACE and Beni-Platzmann theories, which both return plausible results for their respective Einstein and Debye temperatures for the trans- A key limitation of some approaches is the absence of any explicit static disorder term in both the EQACE and Beni-Platzmann models.…”

Section: Debye Modelmentioning

confidence: 99%

High-accuracy transmission and fluorescence XAFS of zinc at 10 K, 50 K, 100 K and 150 K using the hybrid technique

John¹,

Sier²,

Ekanayake³

et al. 2023

J Synchrotron Radiat

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The most accurate measurements of the mass attenuation coefficient for metals at low temperature for the zinc K-edge from 9.5 keV to 11.5 keV at temperatures of 10 K, 50 K, 100 K and 150 K using the hybrid technique are reported. This is the first time transition metal X-ray absorption fine structure (XAFS) has been studied using the hybrid technique and at low temperatures. This is also the first hybrid-like experiment at the Australian Synchrotron. The measured transmission and fluorescence XAFS spectra are compared and benchmarked against each other with detailed systematic analyses. A recent method for modelling self-absorption in fluorescence has been adapted and applied to a solid sample. The XAFS spectra are analysed using eFEFFIT to provide a robust measurement of the evolution of nanostructure, including such properties as net thermal expansion and mean-square relative displacement. This work investigates crystal dynamics, nanostructural evolution and the results of using the Debye and Einstein models to determine atomic positions. Accuracies achieved, when compared with the literature, exceed those achieved by both relative and differential XAFS, and represent a state-of-the-art for future structural investigations. Bond length uncertainties are of the order of 20–40 fm.

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Section: Debye Modelmentioning

confidence: 99%

High-accuracy transmission and fluorescence XAFS of zinc at 10 K, 50 K, 100 K and 150 K using the hybrid technique

John¹,

Sier²,

Ekanayake³

et al. 2023

J Synchrotron Radiat

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“…Usually, the analysis of the temperature-dependent XAFS spectra using the cumulants is expressed in terms of the power moments of the RD function. The first and second XAFS cumulants are given by [8,10,40,41]…”

Section: Formalismmentioning

confidence: 99%

Application of Anharmonic Correlated Debye Model in Investigating Anharmonic XAFS Thermodynamic Properties of Crystalline Silicon

Tien

2022

MaP

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In this work, the temperature dependence of the anharmonic X-ray absorption fine structure (XAFS) and thermodynamic properties of the crystalline silicon (c-Si) have been investigated. The thermodynamic parameters are derived from the influence of the absorbing and backscattering atoms of all their nearest neighbors in the crystalline lattice with thermal vibrations. The Debye-Waller factor and thermal expansion coefficient in the anharmonic XAFS of c-Si were calculated in explicit forms using the anharmonic correlated Debye (ACD) model. This calculation model is developed from the many-body perturbation approach and correlated Debye model using the anharmonic effective potential. The numerical results of c-Si in temperature ranging from 0 to 1500 K are in good agreement with those obtained by the other theoretical procedures and experiments at several temperatures. The analytical results showed that the ACD model is useful in analyzing the experimental XAFS data on c-Si.

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“…Recently, a quantum anharmonic correlated Einstein (QACE) model has been applied to to effectively treat the anharmonic XAFS oscillation of materials [13][14][15]. This model has the advantage that the obtained expressions are explicit and valid even in IJMRA, Volume 07 Issue 06 June 2024 www.ijmra.in Page 2857…”

Section: Introductionmentioning

confidence: 99%

Investigating Anharmonic XAFS Debye-Waller Factor of Crystalline Tungsten Based on Einstein Model

Thuy

2024

IJMRA

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The anharmonic X-ray absorption fine structure (XAFS) Debye-Waller (DW) factor of the crystalline tungsten (W) has been investigated in the temperature-dependent. This DW factor is calculated in explicit forms using the quantum anharmonic correlated Einstein model developed from the correlated Einstein model based on the anharmonic effective potential and the quantum statistical theory. The numerical results of W in the temperature range from 0 to 900 K are in good agreement with those obtained by the other theoretical models and experiments at several temperatures. The analytical results show that the anharmonic correlated Einstein model is suitable for analyzing the experimental XAFS data of metals.

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Investigation of the anharmonic EXAFS oscillation of distorted HCP crystals based on extending quantum anharmonic correlated Einstein model

Cited by 9 publications

References 69 publications

High-accuracy transmission and fluorescence XAFS of zinc at 10 K, 50 K, 100 K and 150 K using the hybrid technique

High-accuracy transmission and fluorescence XAFS of zinc at 10 K, 50 K, 100 K and 150 K using the hybrid technique

Application of Anharmonic Correlated Debye Model in Investigating Anharmonic XAFS Thermodynamic Properties of Crystalline Silicon

Investigating Anharmonic XAFS Debye-Waller Factor of Crystalline Tungsten Based on Einstein Model

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