The effect of weak exchange interaction on electron paramagnetic resonance in dichloro bis-o-phenylene bis-dimethyl arsino nickelate(III) chloride

Abstract

The observation of a single exchange-narrowed E.P.R. line in [NiCl₂-(diars)₂]Cl, a monoclinic crystal with two magnetically inequivalent sites, is shown to be due to g-averaging and hence the concentration dependence of the g-tensor is explained. The lineshape analysis and the angular dependent linewidth data are used to evaluate various Fourier components of the spin-correlation function using Kubo-Tomita theory. The total linewidth is partitioned into secular and non-secular contributions of the broadening mechanisms—dipolar and hyperfine interactions. The angular dependence of the “10/3 effect” observed in X- and Q-bands could not be predicted by either the Blume-Hubbard or the Anderson-Weiss model. In the J regime [Hz ≈ 12 500 G or 3200 G > H ex≈ 700 G > H dipolar,H hyperfine ≈ 70 G] of [NiCl₂(diars)₂]Cl there is paucity of both experimental and theoretical studies.