FT Pulsed EPR/Transient Quantum Spin Nutation Spectroscopy Applied to Inorganic High-Spin Systems and a High-Spin Polymer as Models for Organic Ferromagnets

Electron spin transient nutation method based on pulsed EPR spectroscopy was for the first time exploited for the identification of effective molecular spin multiplicities of a quasi one-dimensional organic high-spin polymer, showing the effective molecular high, spins with the spin quantum number S>2 featured in the nutation spectra of the polymer. It was concluded that the polymer was characterized as the mixture of molecular high-spin assemblages, supporting that the results from the susceptibility measurements of the same polymer suggested the existence of high-spin assemblages with an average S=2. The pulsed EPR nutation spectroscopy was also applied to high-spin systems of Mn2+(S=5/2) and Cr3+(S=3/2) in MgO powder, demonstrating the inherent advantages of the nutation spectroscopy. Particularly, the nutation method showed that Cr3+ in MgO is located in lower symmetric environments distorted from octahedral symmetry. The nutation spectra for the Cr3+-doped MgO powder indicated the occurrence of multiple quantum transitions for S=3/2.