Ab initio calculations of the electronic structure and specific optical features of β-LiNH4SO4 single crystals

Rudysh, M. Ya.; Brik, M.G.; Stadnyk, V. Yo.; Brezvin, R. S.; Shchepanskyi, P. A.; Федорчук, А.О.; Khyzhun, O.Y.; Kityk, I.V.; Piasecki, M.

doi:10.1016/j.physb.2017.10.085

Cited by 24 publications

(6 citation statements)

References 35 publications

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“…2 ). Additional support to the energy positions found in this work for structures A (A′) and B (B′), and the corresponding site assignments, is provided by previous X-ray photoelectron spectroscopy (XPS) results on N 1 s core-level binding energies for different compounds bearing NH 399.5 ± 0.2 eV 14 , 400.4±0.1 eV 15 , 400.49±0.08 eV 16 and NO 404.2 eV 17 , 403.9 eV 17 , 403.7 eV 18 , 403.6 19 groups.…”

Section: Resultssupporting

confidence: 82%

Investigating the electronic structure of high explosives with X-ray Raman spectroscopy

Paredes-Mellone

Nielsen

Vinson

et al. 2022

Sci Rep

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We investigate the sensitivity and potential of a synergistic experiment-theory X-ray Raman spectroscopy (XRS) methodology on revealing and following the static and dynamic electronic structure of high explosive molecular materials. We show that advanced ab-initio theoretical calculations accounting for the core-hole effect based on the Bethe-Salpeter Equation (BSE) approximation are critical for accurately predicting the shape and the energy position of the spectral features of C and N core-level spectra. Moreover, the incident X-ray dose typical XRS experiments require can induce, in certain unstable structures, a prominent radiation damage at room temperature. Upon developing a compatible cryostat module for enabling cryogenic temperatures ($$\approx$$ ≈ 10 K) we suppress the radiation damage and enable the acquisition of reliable experimental spectra in excellent agreement with the theory. Overall, we demonstrate the high sensitivity of the recently available state-of-the-art X-ray Raman spectroscopy capabilities in characterizing the electronic structure of high explosives. At the same time, the high accuracy of the theoretical approach may enable reliable identification of intermediate structures upon rapid chemical decomposition during detonation. Considering the increasing availability of X-ray free-electron lasers, such a combined experiment-theory approach paves the way for time-resolved dynamic studies of high explosives under detonation conditions.

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Section: Resultssupporting

confidence: 82%

Investigating the electronic structure of high explosives with X-ray Raman spectroscopy

Paredes-Mellone

Nielsen

Vinson

et al. 2022

Sci Rep

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“…The user can plot any combination of the five described properties on the same figure for convenience, as well as being able to modify all the figures parameters like in any other kind of figure in PyDEF 2.0. A sample is shown on Figure ɛ = ɛ 1 + iɛ 2 the permittivity of the material, where ɛ 1 , ɛ 2 are real components order 2 symmetrical tensors (matrices) and i 2 = −1

n = \frac{\sqrt{ɛ_{1} + \sqrt{ɛ_{1}^{2} + ɛ_{2}^{2}}}}{\sqrt{2}}

refractive index

k = \frac{\sqrt{- ɛ_{1} + \sqrt{ɛ_{1}^{2} + ɛ_{2}^{2}}}}{\sqrt{2}}

extinction coefficient

R = \frac{{(n - 1)}^{2} + k^{2}}{{(n + 1)}^{2} + k^{2}}

reflectivity of the material …”

Section: New Features In Pydef 20mentioning

confidence: 99%

PyDEF 2.0: An Easy to Use Post‐treatment Software for Publishable Charts Featuring a Graphical User Interface

2018

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Herein we present an open‐source program automating the post‐treatment of solid‐state ab initio calculations performed with VASP, the most used solid‐state simulation package. The program plots Density of States (DOS) and Band Diagrams, enabling the user to conduct efficiently a detailed study of electronic properties of a material. Our tool includes a complete module dedicated to point defects studies, proposing various corrections which can be activated at will and innovative property calculations such as defect concentrations. This is the first program of its kind to offer a direct plot of the stability domain of the studied matrix with respect to its components’ chemical potentials. We also implemented the retrieval of optical indices ɛ1 and ɛ2, the computation of the refractive and extinction coefficients (n, k) and the reflexivity R of the material. All features of the piece of software are available through a thoroughly designed user‐friendly, elegant and efficient Graphical User Interface (GUI) to be accessible to material scientists with various expertises, from both the experimental and theoretical sides. All figures are of publishable quality and can be customized as desired. © 2018 Wiley Periodicals, Inc.

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“…To compare the optimized crystal structure with the experimental (Table 2), the parameter of relative deviation of the unit cell volume d r and relative root mean squared deviation D r of the distance matrix d ij were used as was done, for example, in refs. [44, 45] The relative deviation of the unit cell volume d r can be found as

\begin{equation} {d_{\rm{r}}} = \frac{{V{{_{\rm{c}}^{{\rm{(opt)}}}}^{1/3}} - V{{_{\rm{c}}^{(\exp )}}^{1/3}}}}{{V{{_{\rm{c}}^{(\exp )}}^{1/3}}}}, \end{equation}

where

V_{\rm{c}}^{{\rm{(opt)}}}

and

V_{\rm{c}}^{{\rm{(exp)}}}

are the optimized and experimental unit cell volumes, respectively. The calculated values of the deviation of the cell volume from the experimental are d r = 0.017 for LDA and d r = 0.013 for GGA functionals.…”

Section: Resultsmentioning

confidence: 99%

Electronic Structure, Optical, and Elastic Properties of AgGaS₂ Crystal: Theoretical Study

Rudysh

Ftomyn

Shchepanskyi

et al. 2022

Advcd Theory and Sims

Self Cite

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A comprehensive theoretical study of the structure, electronic, optical, and elastic properties of ternary semiconductor silver thiogallate crystal AgGaS2 is carried out based on the density functional theory and dipole electron shifting model (DES) for finding a structure–properties relationship. The deformation and displacement parameters, describing the deviation of the structural parameters of AgGaS2 from ideal chalcopyrite structure, are determined. It is noticed that the significant discrepancies concerning peculiarities of the band structure between initial results of the DFT‐based calculation and the experiment for the titled crystal have been efficiently eliminated by choosing the proper DFT + U approach. By utilizing the calculated dielectric function for two principal directions, the refractive indices and extinction coefficients dispersions are determined. For the first time, the linear electro‐optic properties, electrogyration coefficients, and second‐order nonlinear optical coefficients of AgGaS2 crystals are calculated in the frame of the DES model. The elastic properties of the AgGaS crystal are analyzed in the frame of the calculated full matrix of elastic coefficients. A number of parameters, such as Young's modulus E, Poisson's ratio ν, bulk B, and shear G moduli are predicted for the crystal. The calculated anisotropy coefficients for the moduli show very good agreement with ones available from experiment.

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Ab initio calculations of the electronic structure and specific optical features of β-LiNH4SO4 single crystals

Cited by 24 publications

References 35 publications

Investigating the electronic structure of high explosives with X-ray Raman spectroscopy

Investigating the electronic structure of high explosives with X-ray Raman spectroscopy

PyDEF 2.0: An Easy to Use Post‐treatment Software for Publishable Charts Featuring a Graphical User Interface

Electronic Structure, Optical, and Elastic Properties of AgGaS₂ Crystal: Theoretical Study

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Ab initio calculations of the electronic structure and specific optical features of β-LiNH4SO4 single crystals

Cited by 24 publications

References 35 publications

Investigating the electronic structure of high explosives with X-ray Raman spectroscopy

Investigating the electronic structure of high explosives with X-ray Raman spectroscopy

PyDEF 2.0: An Easy to Use Post‐treatment Software for Publishable Charts Featuring a Graphical User Interface

Electronic Structure, Optical, and Elastic Properties of AgGaS2 Crystal: Theoretical Study

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Electronic Structure, Optical, and Elastic Properties of AgGaS₂ Crystal: Theoretical Study