Photoelectron spectroscopic study of hydroxylamine (NH2OH) and o-methylhydroxylamine (NH2OCH3)

Hei photoelectron spectra of hydroxylamine and o-methylhydroxylamine in the gaseous phase have been measured below 20 eV, and have been resolved into five and seven ionization bands, respectively, corresponding to p-type molecular orbitals. On the basis of available ab initio MO calculations by Fink et al., the p-type photoelectron bands of hydroxylamine have well been interpreted in terms of a trans staggered form already known as the most stable conformation in the gaseous phase. Orbital assignments on the p-type bands of o-methylhydroxylamine have been made on the basis of CNDO/2 calculations which were also carried out in the present work, except for the first two bands whose assignments were based on orbital-interaction considerations. An ionization-energy sum rule proposed previously has also been tested for the compounds studied here.