The nitrogen–hydrogen fluoride dimer: Infrared spectroscopy and vibrational predissociation

The ν1 infrared spectrum of N2–HF has been observed at sub-Doppler resolution using an infrared laser–molecular beam apparatus which is based on the optothermal detection method. This spectrum has been used to obtain the following molecular constants: B1=0.107 19±0.0001 cm−1 and ν0=3918.2397±0.005 cm−1. In addition, the Stark spectrum of the R1 transition was recorded in order to determine the ground (μ0=1.991±0.008 D) and excited vibrational (μ1=2.106±0.008 D) state dipole moments of the complex. Spectra recorded at the highest resolution clearly show homogeneous broadening of the individual rotational transitions giving a predissociation lifetime of 44±10 ns.