Study of the Rotational Spectrum of the Ne-N2O van der Waals Dimer with a Fourier Transform Microwave Spectrometer.

Rotational spectra of six isotopomers of the van der Waals dimer Ne-N2O, namely 20Ne-14N14NO, 22Ne-14N14NO, 20Ne-14N15NO, 22Ne-14N15NO, 20Ne-15N14NO, and 22Ne-15N14NO, were measured in the frequency range between 5 and 18 GHz using a pulsed beam cavity Fourier transform microwave spectrometer. The spectra are those of prolate asymmetric rotors and are in accord with a T-shaped structure of the complex. Both a- and b-type transitions were measured. Nuclear quadrupole hyperfine patterns of the rotational transitions due to the 14N nuclei were observed and analyzed. The rotational and centrifugal distortion constants were determined, as well as the quadrupole coupling constants chiaa and chibb, for both terminal and central 14N nuclei. The distance from the center of mass of the N2O subunit to the Ne atom and the angle between this distance and the N2O axis were derived from the rotational constants. The structural parameters indicate that the Ne atom is on average closer to the O atom than to the terminal N atom. Copyright 1998 Academic Press.