Dr. Robinson Cortes-Huerto
Robin Cortes-Huerto studied Physics and completed his Licentiate and MSc degrees at the Universidad Nacional de Colombia in Bogota. He moved to Belfast in 2006 and earned a PhD in 2010 under the supervision of Prof. Pietro Ballone. After two postdoctoral positions at the CINaM-Marseille, INSP-Paris and CEA-Saclay, he joined the group of Prof. Kurt Kremer at the Max Planck Institute for Polymer Research (MPI-P). At the MPI-P, he was awarded an Alexander von Humboldt Research Fellowship in 2015, and in 2019 he was appointed Group Leader. His research activity involves the development of the adaptive resolution method as a tool to compute free energy differences and to perform non-equilibrium molecular dynamics simulations.
Free Energies and Non-equilibrium Simulations in the Adaptive Resolution Method
In the Hamiltonian adaptive resolution framework, a physical system is in thermal and chemical equilibrium with a reservoir of ideal gas particles. We use this simulation setup as a spatially-resolved thermodynamic integration method. Namely, we interpret atomistic and ideal gas systems as two limiting states. The position within the simulation box defines a thermodynamic path that enables the calculation of the corresponding difference in free energy. We apply this method to the calculation of chemical potentials and solvation free energies of molecular systems.
The proposed simulation setup resembles the definition of the grand canonical ensemble in which a system is in thermal and chemical equilibrium with a reservoir of infinite size. A particle insertion/deletion algorithm is introduced in the ideal gas system to ensure the latter requirement. By modifying boundary conditions in the simulation box, we use this approach to study pressure-driven flows in molecular liquids. A crucial advantage of this method is that, on average, conserves linear momentum. This condition permits the study of various out-of-equilibrium conditions in complex molecular systems.
Fluctuations, finite-size effects and the thermodynamic limit in computer simulations
Computer simulations display finite-size effects due to the use of periodic boundary conditions and the difference between statistical ensembles. In this context, the spatial block analysis method enables us to extrapolate thermodynamic quantities from finite-size computer simulations. Building upon these results, we have introduced an accurate and efficient approach to obtain asymptotic thermodynamic properties, including chemical potentials, from small-sized molecular dynamics simulations. We use this technique to study solvation thermodynamics of liquids and liquid mixtures.