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Exchange Spin Coupling from Gaussian Process Regression

preprint
revised on 02.07.2020 and posted on 03.07.2020 by Marc Philipp Bahlke, Natnael Mogos, Jonny Proppe, Carmen Herrmann
Heisenberg exchange spin coupling between metal centers is essential for describing and understanding the electronic structure of many molecular catalysts, metalloenzymes, and molecular magnets for potential application in information technology. We explore the machine-learnability of exchange spin coupling, which has not been studied yet. We employ Gaussian process regression since it can potentially deal with small training sets (as likely associated with the rather complex molecular structures required for exploring spin coupling) and since it provides uncertainty estimates (“error bars”) along with predicted values. We compare a range of descriptors and kernels for 257 small dicopper complexes and find that a simple descriptor based on chemical intuition, consisting only of copper-bridge angles and copper-copper distances, clearly outperforms several more sophisticated descriptors when it comes to extrapolating towards larger experimentally relevant complexes. Exchange spin coupling is similarly easy to learn as the polarizability, while learning dipole moments is much harder. The strength of the sophisticated descriptors lies in their ability to linearize structure-property relationships, to the point that a simple linear ridge regression performs just as well as the kernel-based machine-learning model for our small dicopper data set. The superior extrapolation performance of the simple descriptor is unique to exchange spin coupling, reinforcing the crucial role of choosing a suitable descriptor, and highlighting the interesting question of the role of chemical intuition vs. systematic or automated selection of features for machine learning in chemistry and material science.

Funding

Deutsche Forschungsgemeinschaft (DFG) HE 5675/6-1

Deutsche Forschungsgemeinschaft (DFG) 389479699/GRK2455

History

Email Address of Submitting Author

carmen.herrmann@chemie.uni-hamburg.de

Institution

University of Hamburg

Country

Germany

ORCID For Submitting Author

0000-0002-9496-0664

Declaration of Conflict of Interest

No conflict of interest

Exports