Estimates of magnetic resonance parameters in semi-empirical quantum chemistry

摘要

The possibility to reliably estimate the magnetic resonance parameters (MRP) can significantly increase the information content of experimentally recorded spectra. Here we consider in detail semi-empirical estimates of the ESR spectra parameters: isotropic hyperfine coupling constants, anisotropic hyperfine coupling tensors and ^-tensors. The results show that the semi-empirical procedures give estimates of MRP comparable in quality with those of complicated ab initio and DFT schemes. It was underlined that a special attention should be given to geometric parameters of free radicals. The automatic procedure to determine molecular geometries of free radicals on the ground of their spectral characteristics was discussed.