Photodetachment Cross Section, Electron Affinity, and Structure of the Negative Hydroxyl Ion

Experimental data on the cross section for photodetachment of ${\mathrm{OH}}^{-}$ and ${\mathrm{OD}}^{-}$ ions are given and used to argue that the equilibrium internuclear distance $r_e\left({\mathrm{OH}}^{-}\right)=r_e\left(\mathrm{OH}\right)\pm 0.002$ Å, that the vibrational frequency ${\omega }_e\left({\mathrm{OH}}^{-}\right)=3735\mathrm{}\pm 560$ ${\mathrm{cm}}^{-1\mathrm{}}$, and that the OH electron affinity E.A.(OH) = 1.83±0.04 eV. Thus, the structure of ${\mathrm{OH}}^{-}$ and OH are remarkably similar, which is consistent with the theoretical predictions of Cade.