FP-LAPW investigation of mechanical and thermodynamic properties of X₂O (X = Na and K) under pressure and temperature effects

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• 作者：Kada Bidai^a ; ^d ; Mohammed Ameri^a ; ^b ; ^d ; ¹ ; ^{lttnsameri@yahoo.fr" class="auth_mail" title="E-mail the corresponding author} ; ^{mohammed.ameri@univ-sba.dz" class="auth_mail" title="E-mail the corresponding author} ; Djillali Bensaid^a ; ^d ; Slamani Amel^a ; ^d ; Ibrahim Ameri^b ; ^d ; Y. Al-Douri^c ; ^d
• 关键词：Anti-fluorite ; Na2O and K2O ; FP-LAPW ; GGA ; Structural properties ; Thermodynamics properties
• 刊名：Optik - International Journal for Light and Electron Optics
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：127
• 期：12
• 页码：5155-5162
• 全文大小：1054 K

文摘

In this paper the ground-state structural, elastic and thermodynamic properties of alkali-metal oxides X₂O (X = Na and K) binary compounds at different pressures and temperatures are investigated by using full-potential augmented plane wave plus local orbitals method (FP-LAPW) within density functional theory, using generalized gradient approximation (GGA). The calculated results are in excellent agreement with the available experimental data and other theoretical results. The thermodynamic properties of Na₂O and K₂O are predicted by using the quasi-harmonic Debye model. The pressure–volume–temperature (P–V–T) relationship, the variations of the bulk modulus B, heat capacity C_V and Cp with pressure P and temperature T, thermal expansion coefficient α and Debye temperature are obtained systematically in the ranges of 0–80 GPa and 0–1200 K.