Choosing reference samples for EPR concentration measurements. Part 4. Systems of S = 52

The papers of this series provide tabulated values that characterize the specific intensity of electron paramagnetic resonance (EPR) signals (signal area per paramagnetic center) for a wide range of paramagnetic species of various classes. These data enable one to choose a reference material producing an EPR signal close in specific intensity to the signal of the species to be quantitated in the unknown or to determine a correction factor when the specific intensities of the two signals are substantially different. The tabulated values comprise transition probabilities and the derivatives of the resonance fields with respect to frequency obtained by exact diagonalization of spin Hamiltonian matrices; they can be used in field-swept X-band EPR quantitations of solids. This part covers the S = 52 paramagnetic centers in cubic and some axial crystal fields.