Observation and analysis of the nu3 band of NH3+

Abstract

The nu3 degenerate vibration–rotation band of the ammonia cation NH3+ was observed and analyzed. The spectrum was detected in direct absorption using a tunable difference frequency spectrometer combined with velocity modulation. The ion was produced in a 6 kHz ac discharge with a gas mixture of He:H2:NH3 (~250:8:1) and with a total pressure of ~6 Torr. Spin–rotation splittings for most Q-branch transitions were well resolved and spin–rotation interaction constants were determined. A symmetric rotor Hamiltonian with A1–A2 splittings and l resonance was used to analyze the spectrum. The spectral pattern indicates that NH3+ is a planar molecular with D3h symmetry, consistent with a 2A"2 ground electronic state.

Files

Additional details