This practical session introduces participants to molecular simulations of adsorption phenomena in nanoporous materials by combining Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) techniques. Using the LAMMPS molecular simulation package, participants will study the adsorption of water molecules inside nanopores.

Objectives:

• Explain the basic principles of GCMC and MD, and why their combination is useful for adsorption studies.
• Understand the role of the grand canonical ensemble in modeling sorption in porous solids.
• Set up and run short GCMC–MD simulations of water in nanoporous silica using LAMMPS.
• Visualize and interpret molecular configurations to identify adsorption sites and pore filling behavior.
• Recognize the limitations of short illustrative runs and how these simulations can be extended to generate full adsorption/desorption isotherms in research applications.

This lab course is suited to students from the M1 level with a background in statistical physics and basic programming.

The session begins with a brief theoretical overview of the GCMC and MD methods and their coupling. GCMC operates in the grand canonical ensemble, where the number of molecules fluctuates according to a defined chemical potential. MD simulations, in turn, are used to equilibrate and relax the system between insertion/deletion attempts, ensuring equilibrated structural configurations. Together, this coupling enables the simulation of adsorption in nanopores under controlled thermodynamic conditions. Participants will then gain hands-on experience in preparing a simulation box, setting up the necessary interactions, and running short GCMC–MD simulations. While a complete adsorption isotherm is beyond the scope of the session on standard computers, participants will observe how water molecules occupy the pore at a fixed chemical potential. The practical will also include visualization and analysis of simulation trajectories to identify adsorption sites, structural relaxation of the confined fluid and topological analysis of the obtained structure. This session illustrates the conceptual and practical workflow for sorption studies, including both theoretical understanding and technical skills needed to extend these simulations to more complex systems or larger-scale studies in their own research.

LOCATION

PEI - 1270 rue de la piscine