A photoionization study of PH: PH2 revisited

Abstract

The photoion yield curve of PH⁺ (PH) is presented, from threshold to 1040 Å. The adiabatic ionization potential of PH is 10.149±0.008 eV. Extensive autoionization structure is observed and analyzed. It is attributed to several Rydberg series, whose mutual convergence limit is 11.852±0.002 eV, and corresponds to the onset of PH⁺ (a ⁴Σ⁻). The photoion yield curve of AsH⁺ (AsH) is juxtaposed, and shown to have a similar pattern. A new photoion yield curve of PH⁺₂ (PH₂) is shown, where the source of PH₂ is the H+PH₃ reaction. The new results corroborate the earlier data (based on the pyrolysis of benzylphosphine) regarding the adiabatic ionization potential of PH₂ to form X̃ ¹A₁, and the presence of broad autoionizing structure. They also display less scatter, and enable one to estimate the onset for ã ³B₁ to be about 0.70 eV above X̃ ¹A₁. From the analogous behavior of the AsH⁺₂ (AsH₂) curve, the a ³B₁–X ¹A₁ splitting in AsH⁺₂ is estimated to be 0.58–0.68 eV.