Muoniated radical states in the group 16 elements: Computational studies

Recent experimental studies on positive muon implantation in silicon, selenium, and tellurium have been interpreted on the basis that the primary paramagnetic species observed is XMu (X=S, Se, or Te), the muonium-substituted analog of the appropriate diatomic chalcogen monohydride radical. However, temperature-dependent signal visibility, broadening, and hyperfine shift effects remain puzzling. The interplay of degeneracy, spin-orbit coupling, and vibrational averaging in these species makes them computationally challenging despite their small size. In this work computational studies are carried out on all hydrogen isotopomers of the series OH, SH, SeH, and TeH. Several different methodological approaches are compared, and the effects of wavefunction symmetry, spin-orbit coupling, and zero-point vibrational corrections on the isotropic and anisotropic components of the hyperfine interaction are examined. Additionally, some models of the Mu site in rhombic sulfur are briefly considered.