Dynamics of muoniated radical states in phthalocyanines

Abstract

This work reports a spectroscopic and spin-dynamics [mu]SR study of the positive muon states formed in the phthalocyanines Zn-Pc, H2-Pc and Cu-Pc. In Zn-Pc and H2-Pc, three distinct muoniated radicals are formed, seen to undergo spin-dynamical processes with charge carriers. Two of the states have very similar hyperfine interaction values, and are believed to be due to muon addition at the outer benzene rings. The third one has a significantly lower hyperfine constant, and is tentatively assigned to addition at an inner part of the molecule. In Cu-Pc, the [mu]SR signals found are diamagnetic-like, and the muon seems to be shielded from interactions with charge carriers and local molecular motion.