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Monte-carlo simulation of the counterion configuration in a charged star-branched diblock copolymer in solution.

The researches of the DRECAM are based both on physical and chemical experimentation and on significant theoretical developments. These developments and the comparison with the experiment allow the understanding of the phenomena and the model validation and support lot of research works. The theoretical activities are developed in the following areas : - theoretical chemistry (ab-initio calculations, molecular dynamics, relativistic effects in the f-elements) - physics of the irradiation (defect formation, energy transfer, ...) - physics of plasmas (high electronic density, ultra high laser energy) - solid state and mesoscopic physics - statistical and non-linear physics (chaos, non-linear processes, disordered matter, ...) - physical chemistry (aggregates, soft matter, solutions, ...) - reaction dynamics.  
#414 - Last update : 03/25 2005
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Rodolphe Pollet
The study of chemical properties of molecular complexes in solution or at interfaces cannot ignore the quantum nature of electrons. Ab initio molecular dynamics (e.g., of the Car-Parrinello type) must then supersedes classical simulations. Examples of our contributions in this field are the development of pseudopotentials associated with a plane waves basis set and the calculation of free-energy profiles.
    In this field, the main goal relates to the description of physical phenomena involved in the solvation of an ion and we treat this problem performing classical molecular dynamics simulations of confined clusters. Previously, theses studies require the parameterization of model potentials that is done by carrying out sophisticated ab initio calculations on small systems. The model potentials take into account the main interaction energy terms, i.e.
    The trapping of molecules in a rare gas matrix is simulated using an original method based on molecular dynamics calculations. Absorption and excited spectra are also simulated. Isolation of atomic sodium in solid host xenon matrices:  In collaboration with C. Crépin (LPPM, Orsay), J. G. McCaffrey and M.
Small aggregates possess many specific behaviors absent in the bulk phase. Among them their magnetic properties are considered to have the most important application field, in particular for magnetic recording materials since the recording density, the recording speed, the noise suppression and the life time are remarkably enhanced as the magnetic particle size decreases.
C Angelié
    Molecular dynamics fails for long time phenomena. At the opposite, pure statistical methods (transition state or RRKM theories) get rid of this problem by phase space volume estimate, but assuming the questionable hypothesis of a fast intra dynamics. We have implemented a mixed statistical dynamical treatment which includes intra dynamics by means of kinetic equations for the states populations.
G. Autès, C. Barreteau, D. Spanjaard, M.C. Desjonquères
The magnetic properties (spin and orbital magnetic moments, magneto-crystalline anisotropy energy (MAE)) of nanoparticles, thin films and wires have recently attracted a lot of attention due  to their potential  applications mainly in the Information Technology sector.
G. Autès, C. Barreteau, M.C. Desjonquères, D. Spanjaard
Spin electronics is an emerging science which aims at using the spin of the conduction electrons in electronic devices. In a near future, the fundamental mechanisms of spin transport will be affected by some physical limits linked to a further size reduction towards the nanometer scale. It is thus fundamental to understand these limits and more generally the physics of magnetism and transport in reduced dimensions.


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