Exploring the transformation of matter through molecular dynamics simulations - F. Pietrucci - 31 mars 2015

Fabio Pietrucci - IMPMC

Mardi 31 mars 2015 à 10 h

IMPMC, Université P. et M. Curie, 4, Place Jussieu, 75005 Paris

Salle de conférence, 4^e étage, Tour 22-23, Salle 1

Abstract

Molecular dynamics (MD) simulations are a sort of in-silico microscope disclosing the finest details in the structure and dynamics of matter at atomic resolution. The last years have seen an explosion of smart sampling algorithms that bypass the main limitation of MD, namely the short accessible time scale, and, in addition, allow reconstructing the thermodynamics (free energy lanscapes) and the kinetics of structural transformation processes. In this respect I recently introduced innovative approaches combining together metadynamics, a successful sampling algorithm, with representations of interatomic bond networks borrowed from graph theory (in the spirit of Google's webpage ranking algorithm). I will discuss the benefits of these techniques as applied to two on-going collaborative research efforts at IMPMC: the study of prebiotic formamide-centered chemical reaction networks, and of structural transitions in water ices and other materials. In the former case, for the first time we could reconstruct detailed free energy landscapes of multi-step reactions passing in a seamless way from gas phase to liquid phase. In the latter case, we are developing a new topology-based strategy able to address on the same footing transitions among crystalline as well as amorphous and liquid phases.