Recherche

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Research

Our research objectives are to explain chemical processes occurring on various time and length scales, from the femtosecond regime to "slow", thermally activated processes, and from the molecular scale to the mesoscopic scale. The guidelines for our research activity then consist in

 

  • Describing chemical processes on various length and time scales and identify how molecular scale phenomena can affect larger scale phenomena, including mesoscopic, macroscopic properties and thermodynamics of matter. Numerical statistical mechanics, using for example, but not exclusively, molecular simulations, is at the heart of this approach. This starts from an accurate description of molecular scale phenomena, involving when needed quantum chemistry (ab initio or QM/MM simulations), quantum mechanics for the dynamics of the ions etc. After identification of the prevailing structures and interactions that emerge out of the molecular level, we aim at making the link with macroscopic properties.

  • Coupling our theoretical approach with state-of-the-art experimental techniques. This allows for probing the microscopic structure and dynamics, and offers a landmark to test the theoretical description at molecular level. This includes various spectroscopies, ranging from IR, multi-dimensional IR, to x-ray absorption spectroscopies. We are particularly engaged in developing theoretical approaches to predict and help in the molecular interpretation of these techniques, in close-contact with experimental groups. At a larger scale, we aim at predicting thermodynamical and transport properties with direct comparison to experiment, based on sound molecular descriptions. This is the very framework of statistical mechanics: recovering thermodynamics based on the appropriate chemical and physical ingredients at molecular scale.

  • Exploring a variety of methodological routes, some opened by the group, for this upscaling from molecular to macroscopic scale: design of adequate force fields including coarse grain force fields, development of continous methods (e.g. classical density functional theory), or development of analytical theories. We also aim at developing specific statistical mechanics tools for the comprehensive treatment of the large body of data generated, and analysis of the complex structures and structural dynamics at the molecular level.

 

Within the general theme of condensed-phase processes, our research activities cover the following main areas:

  1. Structure and dynamics of hydration (Daniel Borgis, Anne Boutin, Damien Laage, Casey Hynes, Rodolphe Vuilleumier). Solvent, water in particular, constitues a molecular environment having an active role in a wide range of chemical processes, which we aim at elucidating.

  2. Role of the molecular environment for some key biological functions (Daniel Borgis, Damien Laage, Casey Hynes). We focus here our attention towards two particular biological processes that are strongly influenced by the environment: enzymatic catalysis and protein-protein recognition.

  3. Reactivity of CO2 and water at extreme conditions or under confinement (Anne Boutin, Rodolphe Vuilleumier). The speciation of CO2 and water in high temperature -- high pressure fluids such as molten silicates is the result of the reactivity of these media. Other materials, like clays or porous materials, are reactive to CO2 and/or water with an enhancement of this reactivity from the large surface of contact. As for enzymatic reactions in non-aqueous environments, we aim at developing the study of chemical reactivity in non-traditional environments, here in the context of material and earth sciences.

  4. Structural dynamics and vibrational energy flow in molecular liquids and bio-molecules (Daniel Borgis, Damien Laage, Casey Hynes, Rodolphe Vuilleumier). The focus will be on elucidating the molecular mechanisms underlying the correlated motion of atoms and at the origin of vibrational energy flow in condensed phase systems.