Journées passées > Journée ABINIT 12/06/2017


ABINIT is a package whose main program allows one to find the total energy, charge density and electronic structure of systems made of electrons and nuclei (molecules and periodic solids) within Density Functional Theory (DFT), using pseudopotentials and a planewave or wavelet basis. ABINIT also includes options to optimize the geometry according to the DFT forces and stresses, or to perform molecular dynamics simulations using these forces, or to generate dynamical matrices, Born effective charges, and dielectric tensors, based on Density-Functional Perturbation Theory, and many more properties. Excited states can be computed within the Many-Body Perturbation Theory (the GW approximation and the Bethe-Salpeter equation), and Time-Dependent Density Functional Theory (for molecules). In addition to the main ABINIT code, different utility programs are provided. 
ABINIT is a project that favours development and collaboration

Comité d'organisation : R. CARACAS, C. CALUGARU, S. BARENDSON 


09h30 - 9h45 Accueil / café

09h45 - 10h00 Ralf EVERAERS (Directeur du CBP - ENS de Lyon) 

10h00 - 11h00 Marc TORRENT (CEA Bruyeres)ABINIT: general presentation, physics, algorithms, and parallelism. Applications in Condensed Matter Physics

Abstract : This presentation will begin with a general description of the ABINIT software - an international open-source project - including the different implemented physical theories. We will specifically focus on the collaborative development mode.
The ABINIT code implements "ab initio" physics (in the framework of the Density-Functional Theory) by developing the electronic functions on a plane wave basis. This involves the use of specific algorithms, in particular an iterative diagonalization algorithm. This algorithm has evolved over the years, especially for its adaptation to parallel computers.
Finally, different applications of ABINIT in Condensed Matter Physics will be presented, in particular those conducted at the Theoretical and Applied Physics Department of the CEA-Bruyères-le-Chatel. The various examples will reveal the variety of applicable physical models implemented in the code.

11h00 - 11h30 Coffee break

11h30 - 12h00 Christophe WINISDOERFFER (CRAL - ENS de Lyon) ABINIT en astrophysique

Abstract : Après avoir présenté les objets astrophysiques et les problématiques associées pour lesquels l'utilisation d'un code de DFT est pertinente, j'exposerai quelques résultats récents obtenus au sein du Centre de Recherche Astrophysique de Lyon avec ABINIT.
Dans une seconde partie, plus prospective, je présenterai des évolutions envisageables qui trouveraient rapidement des applications importantes dans différents contextes astrophysiques.

12h00 - 12h30 Ema BOBOCIOIU (LGLTPE - ENS Lyon) : The WURM project –a web-based freely available database of computed physical properties for minerals with a special focus on Raman

Abstract : The WURM project is a database of computed Raman and infrared spectra and other physical properties for minerals. The calculations are performed within the framework of the density-functional theory and the density-functional perturbation theory. The database is freely available for teaching and research purposes and is presented in a web-based format, hosted on the web site. All calculations are performed using the ABINIT software package.

12h30 - 14h30 Lunch break

14h30 - 15h30 Damien CALLISTE (CEA de Grenoble) : A real-space formalism, from usual DFT calculations to a better description of large systems

Abstract : The presentation will start with a DFT study of the kinetics of oxygenrelated defects in silicon. We will show the effects of external modifications, like strain or n/p-doping on the diffusivity of oxygen monomer and oxygen dimers. Both migration energies and diffusivity pre-factors are impacted by doping, while strain induces a minor effect. A charge transfer is responsible of enhanced monomer diffusion in presence of p-doping, which may explain the experimental measurements in heavily B-doped samples.

Then, the presentation will focus on the specificities of wavelet-basis sets, and specifically their real-space locality, allowing for order N complexity in DFT resolution. Moreover, this formalism provides an easy framework to describe local quantities, like atomic charges. It also allows to reuse optimized basis-sets with fragment approaches. Through examples, it should provide a summary of the current developments in the BigDFT project and their current usage in biology and chemistry, while show casing their possible applications in solid state physics.


15h30 - 15h50 Coffee break

15h50 - 16h20 Razvan CARACAS (CNRS / LGLTPE - ENS Lyon) : Isotopes, elastic tensors, and other linear response functionalities of ABINIT 


16h20 - 16h50 Vincenza D'ANNA (LCL - ENS Lyon) : Structural study of alkaline-earth fluorohalides and borohydrides

Abstract : Some examples of the ABINIT package use to the structural characterization of solid state materials are presented. Two classes of compounds will be considered. The first one includes the alkaline-earth fluorohalides. These compounds are receiving significant attention because of their wide applications. Here, the study of their crystallographic and spectroscopic properties will be presented, taking into account the effects of pressure and temperature.

The inorganic borohydrides belong to the second class of materials considered. They were extensively studied in the field of hydrogen storage materials for their high gravimetric and volumetric content of hydrogen. The use of the X-ray technique for the characterization of these compounds does not give a definitive answer, because of the difficulty to resolving the crystallographic positions of H atoms. How DFT studies can provide a relevant contribution to the structural refinement and to the spectroscopic characterization of these compounds will be presented.

16h50 - 17h20 Emmanuel QUEMENER (CBP - ENS Lyon) : Présentation des ressources informatiques du CBP

17h20 - ...  Discussions / Table Ronde / Coffee break

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