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    • Ab initio investigations on lattice dynamics and thermal characteristics of ThO$_2$ using Debye–Einstein model

      M H SAHAFI M MAHDAVI

      Volume 44 Published: 15 April 2021 Article ID 0096

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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/044/0096

    • Keywords

       

      Density functional theory; quasi-harmonic Debye–Einstein model; lattice dynamics; vibrational entropy; Grüneisen parameter; Debye temperature.

    • Abstract

       

      In this study, the lattice dynamics and thermal characteristics of thorium dioxide are calculated using the first principle calculations based on the density functional theory (DFT). The Gibbs free energy, isothermal bulk moduli,Debye temperature, thermal Grüneisen parameter as well as vibrational contributions of Helmholtz free energy, internal energy and entropy of thorium dioxide are studied for the first time under high temperatures and pressures. Thermal properties are compared using generalized gradient approximation (GGA) and local density approximation (LDA) under a novel model based on the quasi-harmonic Debye–Einstein method. The results of the simulation reveal that the lattice constant calculated by LDA is less than the one calculated by GGA, while the Gibbs free energy, Debye temperature, adiabatic and isothermal bulk modulus obtained from LDA are greater than ones obtained from GGA. The volumetric thermal expansion coefficient and vibrational contribution of entropy obtained from GGA and LDA increase with rise in temperature.

    • Author Affiliations

       

      M H SAHAFI M MAHDAVI

      1. Dates

         
        Published
        15 April 2021
        Manuscript received
        17 August 2020
        Accepted
        2 November 2020
        Final version published online
        15 April 2021

    • Bulletin of Materials Science | News

      • Dr Shanti Swarup Bhatnagar for Science and Technology

        Posted on October 12, 2020

        Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
        Chemical Sciences 2020

        Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
        Physical Sciences 2020

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        Posted on July 25, 2019

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