EPR studies of phosphine photofragments in cancrinite matrix at 77K

The far-uv photolysis of phosphine sorbed in cancrinite matrix at 77 K has been studied by epr spectroscopy. Cancrinite is demonstrated to stabilise the photolytically generated radicals ·PH₂, ·P and ·H. Computer simulation of the entire lineshapes has been employed to assess the spin Hamiltonian parameters for both ·PH₂ and ·P. The intensity distribution pattern of the ·PH₂ spectrum at 77 K is indicative of a thermally-equilibrated population of rotational states of this radical in its matrix environment. The similarity of the epr data of ·PH₂ trapped in cancrinite to that isolated in rare gas matrices, as well as theisotropic nature of the³¹P and¹H hyperfine couplings in the former situation, suggest that ·PH₂ is trapped in pseudospherical cavities of cancrinite with minimal matrix perturbations. Marked departures are observed for theg- andA- values of cancrinite-trapped P atoms as compared with the gasphase counterparts.