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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 16: Modeling and Simulation of Soft Matter II

CPP 16.6: Talk

Tuesday, March 19, 2024, 10:45–11:00, H 0106

Mixed-Resolution Force Probe Simulations — Marco Oestereich, Jürgen Gauss, and •Gregor Diezemann — Department Chemie, Johannes Gutenberg-Universitaät Mainz, Duesbergweg 10-14, 55128 Mainz, Germany

Force probe molecular dynamics (FPMD) simulations are a well-established technique to investigate the conformational transitions in complex molecular systems. In a standard version of these simulations one end of the molecule is fixed in space and the other end is pulled apart with a constant velocity, very similar to the experimental protocols of dynamic force spectroscopy. In order to overcome the problem that the pulling velocities accessible in simulations are much larger than those in experiments usually coarse-graining (CG) methodologies are used to speed up FPMD simulations. In order to keep atomistic resolution for the solute allowing for a detailed investigation of conformational kinetics we apply the adaptive resolution scheme (AdResS) in our study. In this scheme the solute and the solvent within a well-defined spherical region are treated in an all-atom (AA) manner. Between this region and a CG region outside there is a hybrid region which allows for switching between the two resolutions. We have shown earlier that this setup works well provided the AA region is large enough and the interactions in the CG region are treated via an iterative Boltzmann inversion procedure(1). We present results for two systems undergoing conformational transitions and demonstrate that also a treatment of the CG part of the system employing an ideal gas approximation works extremely well.

Keywords: force probe simulations; coarse graining; mixed resolution