Résumé | Two new infrared bands in the ν1 fundamental region of N2O are observed in a supersonic jet expansion and assigned to nitrous oxide pentamers. Each band is measured using both 14N2 16O and 15N2 16O. Although they are similar in appearance, the bands have slightly different lower state rotational parameters, and are thus assigned to distinct structural isomers of the pentamer. Cluster calculations using two N2O intermolecular potentials give results in good agreement with the observed spectra, and indicate that the two isomers probably have the same basic structure (which is unsymmetrical), but differ in the alignment (N-N-O or O-N-N) of one or two of the constituent monomers. Calculations using a resonant dipole interaction model also support the proposed assignment and structure. These are the first reported high-resolution spectra for N2O pentamers. |
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