DETERMINATION OF THE HYPERFINE INTERACTION PARAMETERS OF NITROGEN DIOXIDE FROM THE MICROWAVE $SPECTRUM^{*}$

Abstract

“The microwave spectra of $N^{14}O_{2}^{16}$ and $N^{15}O^{16}_{2}$ have been assigned and approximate values of the hyperfine interaction parameters have been determined by Bird and $Baird.^{1}$ The determination of accurate values of these parameters requires a least squares fit of all the data because the observed lines are insensitive to several of the parameters. By combining the $N^{14}O_{2}^{16}$, the $N^{15}O_{2}^{16}$, and $N^{14} O^{16}O^{18}$ (obtained in the course of the present investigation) microwave frequencies in such a fit, fairly accurate values of all the hyperfine interaction parameters have been obtained. The interpretation of these parameters in terms of the electronic structure of the molecule will be briefly discussed. In addition the Stark, effect of the $8_{08}\rightarrow 7_{17}$ transition of $N^{14}O^{16}_{2}$ has been partially resolved. The dipole moment of $NO_{2}$ can be estimated from this.”