Photodetachment of Electrons from Phosphide Ion; the Electron Affinity of PH2

Abstract

The relative cross section for photodetachment of electrons from PH₂⁻ has been measured in the wavelength region 725–1020 nm (1.71–1.22 eV). An ion cyclotron resonance spectrometer has been used to generate, trap, and detect the negative ions, while two light sources have been employed to study photo‐detachment: a 1000‐W xenon arc lamp with grating monochromator and a continuously tunable laser. A single sharp threshold in the cross‐section curve has been observed, and a detailed analysis has yielded a value for the electron affinity, $\mathrm{E.A.}({\mathrm{PH}}_2\text{·) = 1.25 ± 0.03\hspace{0.17em}}\mathrm{eV}.$