Knowledge Bank

Using a Zeeman-modulated cavity spectrometer with a 30 see time constant and a phase locked klystron, we have observed in the products of a discharge-flow system the components of three zero field lines at $65072\pm 3.5$ MHz, $65080.5\pm 2$ MHz, and $65097.5\pm 3.5$ MHz. The Q of the Fabry-Perot cavity is about 10 000, and the magnetic field is swept from 0 to 30 Gauss. Chemical tests indicate that these lines are due to $HO2$, and these frequencies are consistent with the prediction of Hougen $etal,1$ for the $N=1\to 0$ transition. Tentatively these are identified as pertaining to the $(N=1,J=1/2)\to (N=0,J=1/2)$ transition as split by the hydrogen hyperfine interaction. The change in frequency of the Zeeman components with magnetic field is approximately consistent with the g values for this transition. However, because of strong interaction between the proton and electron spins, J may not be a good quantum number. A search for other transitions is in progress.