MICROWAVE SPECTRA AND STURCTURES OF THE $N_{2}O$-HF AND $N_{2}O$-DF COMPLEXES.

Abstract

Rotational spectra for the two-structural isomers of the $N_{2}O$-HF and $N_{2}O$-DF complexes were measured using a pulse-beam, Fourier transform microwave spectrometer. Rotational transitions were measured to an accuracy of 10 kHz for ONN-HF and ONN-DF. These data were fit to obtain values for B and $D_{J}$. These data are consistent with linear or nearly linear structures with the H of HF bonded to the terminal N of $N_{2}O$. A pseudo-diatomic analysis was used to obtain values for the force constant $k_{s}$ and the stretching frequency $\nu_{5}$ of the weak bond. Thirteen new transitions were measured to an accuracy of 60 kHz for the bent structural isomers, NNO-HF and NNO-DF. These data, combined with previous microwave data were fit to obtain values for $(A + \Delta_{k}), B$, and C, and four quartic distortion parameters, $\Delta_{J}, \Delta_{Jk},\delta_{k}$ and $\delta_{k}$. The centrifugal distortion constants were used in an analysis of the stretching and bending force field parameters $f_{RR}$ and $f_{99}$. The bending force constant $f_{ee}$ is very small, indicating a large amplitude in-plane bending vibration due to the zero-point energy. The contribution of the H(D) atom to centrifugal distortion parameters is shown to be very small, and this results in a considerable simplification of the analysis.