Knowledge Bank

The $J=9/2\leftarrow 7/2,2\pi 3/2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\pi 1/2$, ground vibrational state transitions of $^{35}ClO $ and $\mathrm{<mrow\; data-mjx-texclass="ORD">37</mrow>}ClO$ and the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\pi 3/2$, excited vibrational state transitions of $\mathrm{<mrow\; data-mjx-texclass="ORD">35</mrow>}ClO$ have been observed in the 164-167 GHz region. Additional measurements have also been made on the $J=3/2\leftarrow 1/2$ and $J=5/2\leftarrow 3/2$ transitions of both the ground and excited vibrational states. All measurements were made using millimeter oscillators which were phase locked to harmonics of the X-band source of a Hewlett-Packard microwave spectrometer. Splittings of several of the $\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\pi 3/2$ transitions were resolved at low pressure with the local magnetic field carefully nulled. Using the off diagonal matrix elements tabulated by $Meerts,1$ it was possible to obtain an excellent fit to all of our observed transitions. The most significant change from previously determined $parameters2$ is in the centrifugal distortion constant which now is in excellent agreement with the vibrational frequency measured by $Menzies,3$ et al. The revised parameters for the $v=0$ state will be presented and compared with those determined for $v=1$.