I joined the theory group at the Max Planck Institute for Polymer
Research as a postdoctoral fellow in February 2015.
My position is funded by the collaborative research center TRR 146:
Multiscale Simulation Methods for Soft Matter Systems. Within the TRR
146, I work on many-body effects and optimized
mapping schemes for systematic coarse-graining. My current research
focusses on the extension of existing coarse graining schemes to include
3-body nonbonded interactions and the implementation in the coarse
graining toolkit VOTCA-CSG.
I obtained my PhD at Johannes Gutenberg-University Mainz in the
Condensed Matter Theory Group group KOMET 331, supervised by Prof.
Friederike Schmid in 2015 in collaboration with the SCHOTT AG in Mainz.
In my PhD, I focussed on classical and ab initio molecular dynamics
simulations of silicate and borate glasses and melts.
During my studies, I received a
Diploma in Physics (Dipl.-Phys.) from Johannes Gutenberg-University in
Mainz (2010) and a B.Sc. with Honours from the University of Canterbury
in Christchurch, New Zealand in 2007.
Published in the group
Ultra-Coarse-Graining of Homopolymers in Inhomogeneous Systems
F. Berressem, C. Scherer, D. Andrienko, A. Nikoubashman
Computing Inelastic Neutron Scattering Spectra from Molecular Dynamics Trajectories
T. Harrelson, M. Dettmann, C. Scherer, D. Andrienko, A. Moule, R. Faller
Kernel-based machine learning for efficient simulations of molecular liquids
C. Scherer, R. Scheid, D. Andrienko, T. Bereau
J. Chem. Theory Comput.,
Current machine learning (ML) models aimed at learning force fields are plagued by their high computational cost at every integration time step. We describe a number of practical and computationally-efficient strategies to parametrize traditional force fields for molecular liquids from ML: the particle decomposition ansatz to two- and three-body force fields the use of kernel-based ML models that incorporate physical symmetries the incorporation of switching functions close to the cutoff and the use of covariant meshing to boost the training set size. Results are presented for model molecular liquids: pairwise Lennard-Jones three-body Stillinger-Weber and bottom-up coarse-graining of water. Here covariant meshing proves to be an efficient strategy to learn canonically averaged instantaneous forces. We show that molecular dynamics simulations with tabulated two- and three-body ML potentials are computationally efficient and recover two- and three-body distribution functions. Many-body representations decomposition and kernel regression schemes are all implemented in the open-source software package VOTCA.
Understanding three-body contributions to coarse-grained force-fields
C. Scherer, D. Andrienko
Phys. Chem. Chem. Phys.,
Coarse-graining (CG) is a systematic reduction of the number of degrees of freedom (DOF) used to describe a system of interest. CG can be thought of as a projection on coarse-grained DOF and is therefore dependent on the functions used to represent the CG force field. In this work we show that naive extensions of the coarse-grained force-field can result in unphysical parametrizations of the CG potential energy surface (PES). This issue can be elevated by coarse-graining the two- and three-body forces separately which also helps to evaluate the importance of many-body interactions for a given system. The approach is illustrated on liquid water where three-body interactions are essential to reproduce the structural properties and liquid methanol where two-body interactions are sufficient to reproduce the main features of the atomistic system.
Comparison of systematic coarse-graining strategies for soluble conjugated polymers
C. Scherer, D. Andrienko
Eur. Phys. J. Spec. Top.,
We assess several systematic coarse-graining approaches by coarse-graining poly(3-hexylthiophene-25-diyl) (P3HT) a polymer showing $\pi$-stacking of the thiophene rings and lamellar ordering of the $\pi$-stacked structures. All coarse-grained force fields are ranked according to their ability of preserving the experimentally known crystalline molecular arrangement of P3HT. The coarse-grained force fields parametrized in the amorphous melt turned out to accurately reproduce the structural quantities of the melt as well as to preserve the lamellar ordering of the P3HT oligomers in $\pi$-stacks. However the exact crystal structure is not reproduced. The combination of Boltzmann inversion for bonded and iterative Boltzmann inversion with pressure correction for nonbonded degrees of freedom gives the best coarse-grained model.