Molecular structure refinement by direct fitting of atomic coordinates to experimental ESR spectra

TL;DR

This paper presents a method to directly refine molecular structures by fitting atomic coordinates to experimental ESR spectra, leveraging advanced spin dynamics simulations and accurate quantum calculations.

Contribution

It introduces a novel approach that bypasses spectral analysis, directly optimizing molecular geometry based on ESR spectra using improved simulation algorithms.

Findings

Successful direct fitting of atomic coordinates to ESR spectra

Addresses local minima in spectral fitting

Enhances accuracy of molecular geometry determination from ESR data

Abstract

An attempt is made to bypass spectral analysis and fit internal coordinates of radicals directly to experimental liquid- and solid-state electron spin resonance (ESR) spectra. We take advantage of the recently introduced large-scale spin dynamics simulation algorithms and of the fact that the accuracy of quantum mechanical calculations of ESR parameters has improved to the point of quantitative correctness. Partial solutions are offered to the local minimum problem in spectral fitting and to the problem of spin interaction parameters (hyperfine couplings, chemical shifts, etc.) being very sensitive to distortions in molecular geometry.