Dg. Fleming et al., HYPERFINE COUPLING-CONSTANTS OF MUONIUM-SUBSTITUTED CYCLOHEXADIENYL RADICALS IN THE GAS-PHASE - C(6)H(6)MU, C(6)D(6)MU, C(6)F(6)MU, Applied magnetic resonance, 13(1-2), 1997, pp. 181-194
Citations number
33
Categorie Soggetti
Spectroscopy,"Physics, Atomic, Molecular & Chemical
Muon spin rotation (mu SR) and avoided level crossing resonance (ALCR)
have been used to determine the hyperfine coupling constants (hfcs) o
f the muonium-substituted cyclohexadienyl radicals C(6)H(6)Mu, C(6)D(6
)Mu and C(6)F(6)Mu in the gas phase, at pressures similar to 1 and 15
atm and temperatures in the range 40-80 degrees C. Equivalent studies
of polyatomic free radicals in gases, by electron spin resonance (ESR)
spectroscopy, are generally not possible in this pressure range. The
present gas phase results support the findings of earlier studies of c
yclohexadienyl radicals in the condensed phase, by both mu SR and ESR.
Minor but not insignificant (similar to 1%) effects on the hfcs are o
bserved, which can be qualitatively understood for such nonpolar media
in terms of their differing polarizabilities. This is the first time
that comparisons of this nature have been possible between different p
hases at the same temperatures. These mu SR/ALCR gas-phase results pro
vide a valuable benchmark for computational studies on radicals, free
from possible effects of solvent or matrix environments.