The 351 nm photoelectron spectra of OH-(NH3)(n) n=1,2 and the deuterated analogs exhibit two broad peaks. Ab initio calculations of the anion and neutral potential-energy surfaces have been carried out using an MP2 (second-order Moller-Plesset)/6-31++G(**) basis set. The geometries, frequencies, and energetics from these calculations aid in the interpretation of the experimental results. An estimate of the OH(NH3) electron affinity is 2.35 +/- 0.07 eV based on experimental and theoretical results. Calculations of the anion vibrational wave functions indicate that following electron photodetachment, the neutral potential-energy surface is accessed from the reactant entrance channel through the transition state region. (C) 2000 American Institute of Physics. [S0021-9606(00)00711-X].