Richert research group

Software development for simulation of time-resolved EPR spectra

From transient EPR (trEPR) spectra, valuable information about the magnetic parameters as well as about the time evolution of the spin-polarisation can be obtained. Therefore, the Python simulation routine teacups is developed to perform corresponding analyses for triplet–doublet pairs, as well as for spin-polarised doublets, triplets, and spin-correlated radical pairs. It enables trEPR spectra to be calculated on the basis of the density matrix formalism and the stochastic Liouville equation. Furthermore, the spectra can be correlated with the time-evolution of the populations of the eigenstates. A modular setup makes the package extensible for future applications.

Reference: Quintes, T.; Weber, S.; Richert, S. Teacups, a python package for the simulation of time-resolved EPR spectra of spin-polarized multi-spin systems. J. Phys. Chem. A 2025, 129, 3375–3388

A neural network for the prediction of the exchange coupling

The exchange coupling of triplet–doublet pairs (TDPs) is experimentally difficult to access but is crucial for the characterization of photoexcited chromophore–radical systems. The net polarization of the quartet spectra of TDPs depends on both the external magnetic field and the exchange coupling JTR. In order to predict the value of JTR from a set of three spectra measured in different EPR bands, a neural network is trained.