Hyperfine sublevel correlation (HYSCORE) spectra for paramagnetic centers with nuclear spin I=1 having isotropic hyperfine interactions

Hyperfine sublevel correlation (HYSCORE) spectra of paramagnetic centers that have nuclei with nuclear spin I = 1 and isotropic hyperfine interactions (HFIs) and arbitrary nuclear quadrupole interactions (NQIs) are shown to consist of ridges that have zero width. A parametric presentation of these ridges is suggested that shows the range of possible frequencies in the HYSCORE spectrum and aids in spectral assignments and rapid estimation of spin Hamiltonian parameters. An alternative approach for the spectral density calculation is presented. This methodology is based on spectral decomposition of the Hamiltonian and requires only the eigenvalues. An atlas of HYSCORE spectra is given in the Supporting Information for this paper. This approach is applied to the estimation of the spin Hamiltonian parameters of the oxovanadium-EDTA complex.