Knowledge Bank

We have observed the pure rotational spectrum of gaseous KOH in the millimete-wave region. Our measurements of the $J=8\to 9,10\to 11,11\to 12,$ and $12\to 13$ transitions are best interpreted in terms of a linear model. As many as 30 vibrational satellites have been assigned for a given rotational transition. The patterns of these satellites are qualitatively similar to those observed for RbOH and $CsOH1$ in that the excited bending mode $(\nu 2)$ has effective rotational constants less than $B0$. Assignments were facilitated by the observation of resolvable splittings of $\Delta$ State doublets. Our value of $B0=8208.6GHz$ does not reproduce the previously reported $spectra.2$ An alternative explanation of this data will be given.