Detailed hyperfine structure of muoniated radicals in planar phthalocyanines

Abstract

Abstract A detailed report of the hyperfine structure of paramagnetic muoniated radicals in the planar phthalocyanine zinc phthalocyanine (ZnPc) is given in this work. The hyperfine parameters of the three muoniated radical states formed in this compound were determined from high transverse-field μ SR measurements of a polycrystalline sample, taking into account the axial symmetry of the hyperfine tensor. States I and II are seen to possess a small dipolar character, consistent with the delocalization of the radical's electron to the inner ring of the phthalocyanine molecule, while state III has a hyperfine structure similar to the Mu BC centre formed in inorganic semiconductors. This suggests that the muon in state III occupies an interstitial position between two stacked phthalocyanine molecules.