Free-jet infrared diode laser spectroscopy of the ν2-band of the Ar-N2O van der Waals complex

The vibration-rotational spectrum of the Ar-N2O van der Waals complex has been recorded in the low-frequency stretching mode region of the N2O-monomer (v(1) similar to 1285 cm(-1)). Almost 400 absorption lines were detected using a free supersonic slit-jet expansion in combination with an infrared tunable diode laser spectrometer. The recorded spectrum was assigned to the v(2)-band of Ar-N2O. Rotational constants as well as a full set of quartic centrifugal distortion constants are reported. The effective geometrical parameters of this T-shaped complex in the V-2-excited state are calculated and found to be R = 3.46(2) Angstrom and theta = 82.9(7)degrees. The band-origin of the spectrum is observed at v(0) = 1285.11907(14) cm(-1) and shows a blue-shift compared to the N2O-monomer spectrum of 0.2158(2) cm(-1). (C) 2001 Elsevier Science B.V. All rights reserved.