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March 30 - April 5, 2008
Welcome
The intrinsic motion of the atoms gives rise to most of the mechanical properties of materials, such as the elasticity, the propagation of sound and the phonon dispersion relations, and to a significant contribution to the thermodynamic properties, such as the specific heat and the thermal expansion. Other essential phenomena, such as the temperature dependence of the band gap in semiconductors and the mechanisms of superconductivity, are strongly affected by the atomic vibrations.
The characteristic frequencies of these atomic collective motions depend in a unique manner on the materials, i.e. on chemical composition, isotopic composition, crystallographic structure, etc.The term vibrational spectroscopies encompasses the group of techniques that aim to characterize these atomic vibrations, i.e. the lattice dynamics for crystalline systems. Some of these techniques are light scattering spectroscopies, such as Raman, infrared and inelastic x-ray scattering. Some others involve particles as a probe, such as inelastic neutron scattering and He scattering. The development of vibrational spectroscopies has been closely followed by parallel improvements in first-principles simulation methods, the state-of-the-art being based on Density Functional Theory. These methods, not only allow the prediction of interesting properties to be examined empirically, but provide as well essential information to prepare successful experiments when there are time constraints, such as when using inelastic x-ray and neutron scattering spectroscopies.This school deals with the basis of Density Functional Theory, Perturbation Theory on Density Functional Theory and how this framework can be employed to calculate most properties achievable empirically to vibrational spectroscopies. In particular, we will be using ABINIT, a free computational code given under the GNU agreement.
The main objective in this school is to give a hands-on introduction to ABINIT, and mainly how to use the code to calculate many different vibrational and thermal properties of materials. Among other experimental observables, we will learn how to calculate phonon dispersion relations, elastic constants, the strength of electron-phonon interaction and Raman spectra.
NO REGISTRATION FEE
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