Electron paramagnetic resonance of magnetically dilute cupric (3d ⁹, ²2D) ion in single crystals of zinc 3-pyridine sulfonate

Single crystals of cupric 3-pyridine sulfonate diluted in the diamagnetic zinc compound were prepared and observed for paramagnetic resonance. The symmetry of the magnetic complex is orthorhombic, with two of the g values only slightly different. The ground state of the ion is d-4 which exhibits practically no orbital angular momentum along z. An analysis of the cupric hyperfme structure at room temperature has been performed, arriving at a value of the polarization of the core in very good agreement with the theoretical estimate. No nitrogen superhyperfine structure is resolved at room temperature, although experiments at 77°K show conclusively interaction with two equivalent nitrogens, which is interpreted in detail.