Hartree-Fock investigation of muon trapping in the chemical ferromagnet 4-(p-chlorobenzylideneamino)-TEMPO

First-principles unrestricted Hartree-Fock theory is used to obtain the tra pping sites for muon and muonium in ferromagnetic p-Cl-Ph-CH=N-TEMPO (4-(p- chlorobenzplideneamino)- 2,2,6,6-tetramethylriperidin-1-yloxyl) and the hyp erfine interaction tensors for these sites. Using the calculated hyperfine interactions to fit the two experimentally observed muon spin rotation freq uencies, it has been concluded that the two most likely candidates for expl aining the experimental data are a muon trapped at the chlorine site and a singlet muonium state at the radical oxygen. The direction of the easy axis is also determined. (C) 2000 Published by Elsevier Science B.V. All rights reserved.