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### G.A. Kaptagay, Yu.A. Mastrikov and E.A. Kotomin

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### S. Piskunov, Y. F. Zhukovskii, M. N. Sokolov and J. Kleperis

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### A.I. Popoola, A.Y. Odusote and O.E. Ayo-Ojo

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### M. Caid, H. Rached, D. Rached, R. Khenata, S. Bin Omran, D. Vashney, B. Abidri, N. Benkhettou, A. Chahed and O. Benhellal

one-particle Schrödinger equation (at fixed energy), and their energy derivatives are multiplied by spherical harmonics. We have used the recently developed LmtART package (LmtART 7) with the electrons exchange-correlation energy described using the Perdew-Wang parameterization of the local density approximation (LDA) [ 10 ]. The details of the calculations are as follows: the charge density and the potential are represented inside the muffin-tin sphere (MTS) spherical harmonics up to l max = 6. The k integration over the Brillouin zone is performed using the

### Piotr Kisała, Waldemar Wójcik, Nurzhigit Smailov, Aliya Kalizhanova and Damian Harasim

. [5] R. K. Yamashita, W. Zou, Z. He, K. Hotate, ”Measurement Range Elongation Based on Temporal Gating in Brillouin Optical Correlation Domain Distributed Simultaneous Sensing of Strain and Temperature,” Photonics Technology Letters, IEEE vol. 24(12), pp. 1006-1008, 2012. [6] E. Roger, A. Khayat, L. A. Utracki, F. Godbile, J. Picot, "Influence of shear and elongation on drop deformation in convergent-divergent flows", International Journal of Multiphase Flow, vol. 26(1), pp. 17-44, 2000. [7] U. Iturraran-Viveros, F. J. Sanchez

### Ramakant Bhardwaj

electronegativity criteria [18] . The partial waves of s p d and f states were taken into account. The E and k convergences were checked subsequently to achieve better accuracy. The calculations were performed for 512 k points (the grid of 8 × 8 × 8) in the Brillouin zone for both the B1 and B2 phases. To obtain the total energy and partial density of states the tetrahedron method of Brillouin zone integration was used [19] . The total energy was computed by reducing the volume from 1.05 V 0 to 0.60 V 0 , where V 0 is an equilibrium cell volume. The calculated total energy

### Tahar Dahame, Bachir Bentria, Houda Faraoun, Ali Benghia and A.H. Reshak

structure and all physical properties calculations, the convergence has been reached for both codes with an energy tolerance of 10 − 6 eV with E cut = 600 eV and a 6 × 6 × 4 mesh grid for Brillouin zone sampling. 2.1 Linear optical properties Linear optical properties described in this work are the absorption coefficient, refractive index and dielectric constant. All these quantities are presented as a function of frequency of the electromagnetic wave that propagates through the crystal. The most important optical property of a material is the complex dielectric

### M.H. Elahmar, H. Rached, D. Rached, S. Benalia, R. Khenata, Z.E. Biskri and S. Bin Omran

the interstitial region. The parameter G max , which defines the magnitude of the largest vector in the charge density Fourier expansion, was chosen to be 14. The Brillouin zone integration was performed using the Monkhorst-Pack method with 3000 k-points in the first Brillouin zone [ 20 ]. The cut-off energy, which defines the separation of valence and core states, was chosen to be −6 Ry. We selected the charge convergence to be 0.0001 during self-consistency cycles. In this framework, the strong Coulomb repulsion between localized f states was treated by adding a

### Guohao Wu, S.K. Zheng and Xiaobing Yan

300 eV for all the computations. The special points sampling integration over the Brillouin zone was carried out using the Monkhorst-Pack method with a 2 × 2 × 2 special-point mesh. All of the structures were allowed to relax using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton scheme with the convergence threshold for the maximum energy change of 2.0 × 10 -5 eV/atom, and the maximum force, maximum stress and maximum displacement tolerances set as 0.05 eV/Å, 0.1 GPa, and 0.002 Å, respectively. These parameters are sufficient for well-converged total