Knowledge Bank

Submillimeter wave laser action has been previously $reported1$ in deuterated fluoroform $(CDF3)$ which is optically pumped by a $CO2$ laser. In this paper, accurate heterodyne measurements are reported for the frequencies of 21 of these laser emissions. Nineteen of these lines can be assigned to the $\nu 5$ degenerate vibrational state. The data were fit with a theoretical expression for the frequencies containing terms up to sixth order in J and K and also containing all important $\ell$-doubling effects. The quality of the fit was excellent, yielding accurate values for many of the molecular constants of the $\nu 5$ state. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$M. S. Tobin and R. D. Felock, Opt. Lett. 5, 430 (1980).