Diode laser spectroscopy of the ν4 band of NH 2OH and the ν5 band of NHDOD

Abstract

Doppler-limited spectroscopy of the ν 4 band (OH bend) of hydroxylamine NH 2OH has been carried out using a diode laser spectrometer in the range 1320 to 1400 cm −1. Hydroxylamine is so close to being a symmetric rotor that in the v 4 = 1 excited state the rovibrational effects cause the b and c molecular axes to be interchanged relative to their orientation in the ground state. The recognition of this fact allowed earlier work on the ν 5 band ( 1) to be corrected. The ν 4 band is perturbed by Coriolis-type interactions with at least two other modes. These are (i) a mainly c-type interaction with the combination band ( ν 6 + ν 9) and (ii) an a-type interaction with what is probably the very weak fundamental ν 8. Effective unperturbed parameters are calculated for the ν 4 band. Accurate constants have been obtained for the ν 5 band (NHD-wagging motion) of the partially deuterated form of hydroxylamine, NHDOD. These are the first gas-phase infrared data on any deuterated form of hydroxylamine.