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We report the photoelectron spectra of several alkoxide and enolate negative ions. The spectra are obtained by crossing a mass-selected negative ion beam with the intracavity beam from an Ar II (488 nm) laser and by energy analysis of the resulting photoelectrons. All of the experimental data show at least partially resolved vibrational structure and indicate a substantial geometry change between the neutral radical and the anion. Analysis of the data yields the following electron affinities (in eV

We have observed the negative ion photoelectron spectrum of the methylnitrene ion, CH3N−, and measured the electron affinity of methylnitrene, EA(CH3N)=0.022±0.009 eV. In addition to detaching the methylnitrene anion to the ground state of CH3N(X̃ 3A2), we also detect the first electronically excited state of methylnitrene, ã 1E. We measure the singlet/triplet splitting to be ΔE(ã 1E−X̃ 3A2)=1.352±0.011 eV. The photoelectron spectrum of CH3N ã 1E contains relatively sharp vibronic structure. Unlike the spectra from H2CC−, the photoelectron spectra for CH3N− show no evidence for a barrier separating the rearrangement of singlet methylnitrene to methyleneimine, [CH31N] → CH2=NH.

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Potential energy, electric dipole moment, and electronic transition moment surfaces have been calculated for the A and X states of NH3 from CASSCF and CEPA electronic wave functions. Anharmonic vibrational term values, Franck–Condon factors, and A–X radiative transition probabilities for the symmetric stretching and bending modes of NH3 and ND3 have been evaluated. The theoretical absorption spectra at room and low temperatures agree well with experimental data. The symmetric stretching mode in the A state has only small intensities in the A–X absorption spectrum. Emission rates from various initial vibronic levels of the A state are given. The ab initio electric dipole moment surfaces for the ground state of NH3 have been used to compute transition moments, which are in good agreement with experimental data.