A5044207730- Advanced Chemical Physics Studies
- Machine Learning in Materials Science
- Aquaculture Nutrition and Growth
- Spectroscopy and Quantum Chemical Studies
- Graphene research and applications
- Boron and Carbon Nanomaterials Research
- Fullerene Chemistry and Applications
- Parallel Computing and Optimization Techniques
- Molecular Junctions and Nanostructures
- Aquaculture disease management and microbiota
- Reproductive biology and impacts on aquatic species
- Quantum and electron transport phenomena
- Semiconductor materials and devices
- Protein Structure and Dynamics
- Computational Drug Discovery Methods
- Photochemistry and Electron Transfer Studies
- 2D Materials and Applications
- Advanced Data Storage Technologies
- Advanced NMR Techniques and Applications
- Enzyme-mediated dye degradation
- Microbial bioremediation and biosurfactants
- Molecular spectroscopy and chirality
- Quantum Dots Synthesis And Properties
- X-ray Diffraction in Crystallography
- Electromagnetic Scattering and Analysis
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
CEA Grenoble
2015-2024
Laboratoire Modélisation et Exploration des Matériaux
2022-2024
Université Grenoble Alpes
2014-2023
RIKEN Center for Computational Science
2020-2023
University of Bristol
2023
UiT The Arctic University of Norway
2023
The Abdus Salam International Centre for Theoretical Physics (ICTP)
2023
Institut Nanosciences et Cryogénie
2013-2022
Institut de Recherche Interdisciplinaire de Grenoble
2020-2022
A comparison of DFT methods Density functional theory (DFT) is now routinely used for simulating material properties. Many software packages are available, which makes it challenging to know the best use a specific calculation. Lejaeghere et al. compared calculated values equation states 71 elemental crystals from 15 different widely codes employing 40 potentials (see Perspective by Skylaris). Although there were variations in values, most recent and converged toward single value, with...
Daubechies wavelets are a powerful systematic basis set for electronic structure calculations because they orthogonal and localized both in real Fourier space. We describe detail how this can be used to obtain highly efficient accurate method density functional calculations. An implementation of is available the ABINIT free software package. This code shows high convergence properties, very good performances, an excellent efficiency parallel
Electronic structure calculations have been instrumental in providing many important insights into a range of physical and chemical properties various molecular solid-state systems. Their importance to fields, including materials science, sciences, computational chemistry device physics, is underscored by the large fraction available public supercomputing resources devoted these calculations. As we enter exascale era, exciting new opportunities increase simulation numbers, sizes, accuracies...
Interpolating scaling functions give a faithful representation of localized charge distribution by its values on grid. For such distributions, using Fast Fourier method, we obtain highly accurate electrostatic potentials for free boundary conditions at the cost O(N log N) operations, where N is number grid points. Thus, with our approach, are treated as efficiently periodic via plane wave methods.
Using the minima hopping global geometry optimization method on density functional potential energy surface we show that landscape of boron clusters is glasslike. Larger have many structures which are lower in than cages. This contrast to carbon and nitride systems can be clearly identified as structure seekers. The differences explain why found nature whereas pure fullerenes not been found. We thus present a methodology make predictions feasibility synthesis new nanostructures.
We demonstrate that Daubechies wavelets can be used to construct a minimal set of optimized localized adaptively contracted basis functions in which the Kohn-Sham orbitals represented with an arbitrarily high, controllable precision. Ground state energies and forces acting on ions calculated this same accuracy as if they were directly basis, provided amplitude these is sufficiently small surface localization region, guaranteed by optimization procedure described work. This approach reduces...
Density Functional Theory calculations traditionally suffer from an inherent cubic scaling with respect to the size of system, making big extremely expensive. This can be avoided by use so-called linear algorithms, which have been developed during last few decades. In this way it becomes possible perform ab-initio for several tens thousands atoms or even more within a reasonable time frame. However, though algorithms is physically well justified, their implementation often introduces some...
The BigDFT project was started in 2005 with the aim of testing advantages using a Daubechies wavelet basis set for Kohn–Sham (KS) density functional theory (DFT) pseudopotentials. This led to creation code, which employs computational approach optimal features flexibility, performance, and precision results. In particular, employed formalism has enabled implementation an algorithm able tackle DFT calculations large systems, up many thousands atoms, effort that scales linearly number atoms....
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We present a method that gives highly accurate electrostatic potentials for systems where we have periodic boundary conditions in two spatial directions but free the third direction. These are needed all kinds of surface problems. Our has an O(N log N) computational cost, N is number grid points, with very small prefactor. This Poisson solver primarily intended real space methods charge density and potential given on uniform grid.
We present the implementation of a full electronic structure calculation code on hybrid parallel architecture with graphic processing units (GPUs). This is performed free software based Daubechies wavelets. Such shows very good performances, systematic convergence properties, and an excellent efficiency computers. Our GPU-based acceleration fully preserves all these properties. In particular, able to run many cores which may or not have GPU associated, thus massive machines. With double...
Unbiased open-ended methods for finding transition states are powerful tools to understand diffusion and relaxation mechanisms associated with defect diffusion, growth processes, catalysis. They have been little used, however, in conjunction ab initio packages as these algorithms demanded large computational effort generate even a single event. Here, we revisit the activation-relaxation technique (ART nouveau) introduce two-step convergence saddle point, combining previously used Lanczós...
We present an implicit solvation approach where the interface between quantum-mechanical solute and surrounding environment is described by a fully continuous permittivity built up with atomic-centered "soft" spheres. This combines many of advantages self-consistent continuum model in handling solutes surfaces contact complex dielectric environments or electrolytes electronic-structure calculations. In addition it able to describe accurately both neutral charged systems. The function,...
During the past decades, quantum mechanical methods have undergone an amazing transition from pioneering investigations of experts into a wide range practical applications, made by vast community researchers. First principles calculations systems containing up to few hundred atoms become standard in many branches science. The sizes which can be simulated increased even further during recent years, and quantum‐mechanical thousands are nowadays possible. This opens new appealing possibilities,...
The computational study of chemical reactions in complex, wet environments is critical for applications many fields. It often essential to the presence applied electrochemical potentials, taking into account non-trivial electrostatic screening coming from solvent and electrolytes. As a consequence, potential has be found by solving generalized Poisson Poisson-Boltzmann equations neutral ionic solutions, respectively. In present work, solvers both problems have been developed. A...
By adding a nonlinear core correction to the well established dual space Gaussian type pseudopotentials for chemical elements up third period, we construct improved Perdew-Burke-Ernzerhof [J. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996)10.1103/PhysRevLett.77.3865] functional demonstrate that they exhibit excellent accuracy. Our benchmarks G2-1 test set show average atomization energy errors of only half kcal/mol. The also remain highly reliable high pressure phases...
We investigate laccase-mediated detoxification of aflatoxins, fungal carcinogenic food contaminants. Our experimental comparison between two aflatoxins with similar structures (AFB1 and AFG2) shows significant differences in detoxification. A multi-scale modeling approach (Docking, Molecular Dynamics, Density Functional Theory) identifies the highly substrate-specific changes required to improve laccase detoxifying performance. employ a large-scale density functional theory-based approach,...
The structural stability of fcc Ni over a very large pressure range offers unique opportunity to experimentally investigate how magnetism is modified by simple compression. K-edge x-ray magnetic circular dichroism (XMCD) shows that ferromagnetic up 200 GPa, contradicting recent predictions an abrupt transition paramagnetic state at 160 GPa. Density functional theory calculations point out the evolution XMCD closely follows p projected orbital moment rather than total spin moment....
A fast and accurate scheme has been developed to evaluate two key molecular parameters (on-site energies transfer integrals) that govern charge transport in organic supramolecular architecture devices. The is based on a constrained density functional theory (CDFT) approach implemented the linear-scaling BigDFT code exploits wavelet basis set. method applied model disordered structures generated by force-field simulations. role of environment taken into account building large clusters around...