  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.
