Project B5: Multi-resolution methods including quantum chemistry, force fields, and hybrid particle-field schemes

Multiscaling techniques that involve a quantum-chemical treatment of the electronic structure for the part with the highest resolution are promising computational tools. They are particularly useful for dealing with problems involving large systems like enzymes, membranes, polymers, etc., where, for example, chemical reactions take place. Having completed in the previous funding period of the TRR (i.e., the first funding period of this project) a corresponding QM/MM implementation that allows to include high-accuracy quantum-chemical methods from either coupled-cluster (CC) theory (i.e., CCSD, CCSD(T), etc.) or of multiconfigurational nature (i.e., CASSCF), we intend to complete the envisioned QM/MM/CG/hPF implementation that extends the QM/MM approach to coarse-grained (CG) treatments. In particular, we plan on using hybrid particle-field (hPF) theory based on its Hamiltonian reformulation, where the latter has been accomplished in the first funding period of this project. This reformulation facilitates the coupling of the regimes of different resolution as well as the use of the intended QM/MM/CG/hPF scheme in molecular dynamics (MD) simulations. In order to reduce the computational cost for the QM part which is the time-determining step of QM/MM and QM/MM/CG/hPF treatments and limits their applicability when using high-accuracy quantum-chemical methods, we propose to
use Cholesky decomposition (CD) of the two-electron integrals to speed up the treatment of the QM region. We intend to implement CD based QM/MM and QM/MM/CG/hPF schemes using CD based nuclear forces to perform corresponding MD simulations. We also propose to implement CD based QM/MM and QM/MM/CG/hPF schemes for the computation of spectroscopic properties (NMR, EPR, vibrational) such that an accurate joint experimental and theoretical spectroscopic characterization of soft-matter systems (e.g., biological systems, molecules in solution or non-crystalline solids) becomes possible. In addition, we intend to extend the CD based schemes to include also those from CC and equation-of-motion CC (for the treatment of excited states) theory, and plan to develop schemes, again using CD techniques in a QM/MM or QM/MM/CG/hPF framework that allow the investigation of large systems under the influence of magnetic fields in a non-perturbative manner. Finally, the project intends to use the developed schemes in applications, in close collaboration with projects B1, B3, and B4 to simulate force-probe experiments and to investigate force fields for hydrated ions.

Wavefunction-Based Electrostatic-Embedding QM/MM Using CFOUR through MiMiC
Till Kirsch, Jógvan Magnus Haugaard Olsen, Viacheslav Bolnykh, Simone Meloni, Emiliano Ippoliti, Ursula Rothlisberger, Michele Cascella, Jürgen Gauss
Journal of Chemical Theory and Computation 18 (1),13-24 (2022)
see publication

Automated determination of hybrid particle-field parameters by machine learning
Morten Ledum, Sigbjørn Løland Bore, Michele Cascella
Molecular Physics 118 (19-20), e1785571 (2020)
see publication

Hybrid particle-field molecular dynamics under constant pressure
Sigbjørn Løland Bore, Hima Bindu Kolli, Antonio De Nicola, Maksym Byshkin, Toshihiro Kawakatsu, Giuseppe Milano, Michele Cascella
Angewandte Chemie International Edition, (2020)
see publication

The Grignard Reaction – Unraveling a Chemical Puzzle
Raphael Mathias Peltzer, Jürgen Gauss, Odile Eisenstein, Michele Cascella
Journal of the American Chemical Society 142 (6), 2984-2994 (2020)
see publication

Hybrid Particle-Field Molecular Dynamics Simulations of Charged Amphiphiles in an Aqueous Environment
Hima Bindu Kolli, Antonio de Nicola, Sigbjørn Løland Bore, Ken Schäfer, Gregor Diezemann, Jürgen Gauss, Toshihiro Kawakatsu, Zhong-Yuan Lu, You-Liang Zhu, Giuseppe Milano, Michele Cascella
Journal of Chemical Theory and Computation 14 (9), 4928-4937 (2018)
see publication

A fundamental catalytic difference between zinc and manganese dependent enzymes revealed in a bacterial isatin hydrolase
Theis Sommer, Kaare Bjerregaard-Andersen, Lalita Uribe, Michael Etzerodt, Gregor Diezemann, Jürgen Gauss, Michele Cascella, J. Preben Morth
Scientific Reports 8 (1), (2018)
see publication