Abstract
The electron spin resonance of the optically induced paramagnetic valence anomalies has been studied in the linear chain complex [Pt(en)2][Pt(en)2Cl2](ClO4)4, en=ethylenediamine. The unpaired spins of S=1⁄2 are found to be confined in the molecular orbitals of dimerized Pt ions and the tightly ligating N atoms and Cl− ions. The states have biaxial symmetries with the principal axes of spins nearly parallel to the crystal axes of the orthorhombic phase. These results support the previous assignment that the induced paramagnetic valence anomalies are neutral solitons. At low temperatures, the resonance spectrum exhibits an evidence that the solitons are fluctuating around their equilibrium positions.
