Place: XL CALPHAD Workshop "From Frist Principles to Multi-Scale Modeling of Materials", Rio de Janeiro, Brazil
In this lecture, first principles methods to calculate vibrational properties of solids will be described. Basic equations governing atomic vibrations in solids will be introduced within the harmonic approximation. The Density Functional Perturbation Method (DFPT) will then be introduced to calculate phonon frequencies and then to derive thermodynamic properties by thermodynamic integration. Limitations of the harmonic approximation will be addressed and the quasi-harmonic approximation will be described to overcome these limitations. Finally, an overview of the Quantum-Espresso code will be given. A practical session will be also given demonstrating with practical examples how to calculate phonons and thermophysical properties with Quantum-Espresso.