Towards a Grand Unified Trajectory Sampling (GUTS) framework: using the statistical mechanics of trajectories to predict and understand rare events in complex molecular systems 

Guest: Prof. Dr. van Erp, Titus S., Department of Chemistry, NTNU, Trondheim, Norway.

Hosted by: Prof. Dr. Peter Bolhuis (UvA), Dr. Jörg Meyer (UL).

A visit of 1 month.

Prof. van Erp is active in the field of molecular simulation, theoretical chemistry, and statistical mechanics of rare event trajectories with the aim of understanding and controlling molecular materials and processes. His research uses numerical calculations to understand and design processes and materials. In his materials research, he applies rare event sampling to atomic and coarse-grained simulations of, for example, nanoporous materials such as zeolites. He recently developed a new sampling methodology, ∞RETIS, which can enhance the efficiency of rare event calculations currently performed within HIMS. This requires intensive collaboration with researchers at HIMS.  To that end Prof. Van Erp will work with researchers from HIMS during his visit to achieve this goal.  In addition, he will also contribute to education in the form of seminars and guest lectures.

During the visit, the main effort will be to initiate and build a collaboration with Prof. Bolhuis and his students on developing the core module for the GUTS framework. This constitutes a novel, robust, flexible, and efficient simulation package to generate and analyse molecular dynamics trajectories, so that it can work together with existing frameworks such as OpenPathSampling and PyRETIS, making the ∞RETIS methodology more accessible to researchers.

Additionally, prof van Erp will explore the integration of techniques such as machine-learned (ML) committor functions, predictive modeling, automated initialization and optimization schemes, and on-the-fly ML force fields. 

As a side product of his visit, prof van Erp will take the opportunity to continue to collaborate on REDOX reactions in water with Dr. Bernd Ensing, and on biological transformations with Dr. Jocelyne Vreede, both at HIMS. 

In collaboration with Dr. Jörg Meyer’s group (Theoretical Chemistry, UL) he will intend to explore possible applications to N2 dissociation on Ru(0001) - a rare event with an extremely small reaction probability under thermal process conditions. A high-dimensional ML-based potential energy surface is available for this system.

In terms of dissemination prof van Erp will deliver several lectures on the ∞RETIS method and the analysis of path data, including applications such as predictive capacity. 

Modeling the (in)stability of copper surfaces under cathodic electrochemical conditions

Guest: Prof. Dr. Manos Mavrikakis, University of Wisconsin - Madison, USA

Hosted by: Prof. Dr. Marc Koper (UL), Dr. Katharina Doblhoff-Dier (UL), Prof. Dr. Peter Bolhuis (UvA)

A visit of 3 months

During his visit, Prof. Manos Mavrikakis will work with the group of Marc Koper in Leiden to investigate the mechanism of instability of copper electrode surfaces during electrocatalytic CO₂ reduction. Mavrikakis is a renowned computational chemist who has recently developed models for the atomic-scale dynamics of copper surfaces in the presence of CO, an intermediate in the reaction. The Leiden group will perform in situ STM studies of the same electrode surface in the presence and absence of CO₂ and CO. The project is expected to shine light on the still unknown mechanism of copper instability. Prof. Mavrikakis will also interact with the computational (electro)chemists in Leiden and Amsterdam, and with the group of Irene Groot.

Guest: Prof. Mattanjah S. de Vries, University of California Santa Barbara, USA (John van Geuns Fellowship)

Hosted by: Prof. dr. Anouk Rijs (VU), Prof. dr. Wybren Jan Buma (UvA), Prof. dr. Jos Oomens (RU)

A visit of 7 weeks

The visit of Prof. M.S. de Vries from the University of California at Santa Barbara builds on common interests with the hosts, Prof. WJ Buma at the UVA and Prof. A.M. Rijs at the VU, especially focusing on excited state dynamics and fundamental photochemistry. Applications range from photo-switching and sunscreen molecules to biomolecular building blocks. Complementary techniques and approaches in the three groups will serve to cross-fertilize each of the research programs. As part of the visit, Prof. de Vries also performs experiments at the molecular beam station at FELIX in Nijmegen. Furthermore he will interact with Prof. K. Keune on the topic of the photochemistry of pigments in classical paintings.