The ionization potentials of ammonia and ammonia-d(3). Measured by photoelectron spectroscopy, and an indo calculation of these values

New high resolution photoelectron spectra of ammonia and ammonia-d(3) are reported. The spectra of both compounds show two ionization processes corresponding to ionization from the 3a and le molecular orbitals. The first band in the photoelectron spectrum of each compound shows a well-resolved vibrational progression which is assigned to v(2), the totally symmetric out-of-plane bending mode. Calculations of the ionization potentials have been carried out using the CNDO/2 and LVDO molecular orbital methods. The INDO method gave better results than the CNDO/2 calculation but both sets of values were higher than the experimental ones.