Electron spin resonance spectra of certain fluorohydride radicals of phosphorus, arsenic, and antimony

Isotropic ESR spectra of a series of phosphorus fluorohydride radicals PH_nF_(4-n), where n = 0-4, have been observed in γ-irradiated solid solutions of PF_3, PF_2H, and PH_3 in neopentane or SF_6. The spectra of AsH_3F and SbH_3F are also reported. The hyperfine interactions of these radicals are consistent with a totally symmetric semioccupied orbital in a framework possessing either C_(2u) or C_s symmetry. The relative merits of Hückel and INDO molecular orbital calculations in predicting the various observed trends are discussed.