Infrared diode laser spectroscopy of the He-N2O van der Waals complex in the 1285 cm−1 region

The rovibrational spectrum of the He-N2O van der Waals complex has been recorded in the N2O-monomer ν1 region (∼1285 cm−1) using an infrared tunable diode laser spectrometer in conjunction with a free supersonic jet expansion and an astigmatic multi-pass absorption cell. Twenty-two lines are assigned to the ν2-band of He-N2O. Rotational constants for the ν2-excited state are derived. The band-origin of the spectrum is determined to be ν0 = 1285.0666(7) cm−1 and shows a blue-shift of 0.1633(8) cm−1 compared with the N2O ν1-band origin.