15min:

HELEN O. LEUNG, Department of Chemistry, Mount Holyoke College, South Hadley, MA 01075-6407.

The rotational spectrum of \chem¹⁵N₂-¹⁴N₂O has been recorded in the 7-19 GHz region using a pulsed molecular beam, Fourier transform microwave spectrometer. Both a- and b-type transitions have been observed. The analysis of the hyperfine structure due to the two ¹⁴N nuclei in the \chemN₂O subunit reveals that the energy levels are doubled, owing to a tunneling motion of the \chem¹⁵N₂ subunit. The rotational constants support a planar, T-shaped structure, with \chem¹⁵N₂ forming the leg of the T. This geometry is consistent with that obtained using infrared spectroscopy. The nuclear quadrupole coupling constants of the two ¹⁴N nuclei indicate that the b-axis of the complex forms an angle between 10-12^\circ with the \chemN₂O axis.