Knowledge Bank

We predict over 300 new submillimeter-wave (SMMW) laser emission lines obtainable by the optical pumping of $CDF3$ with isotopic $CO2$ and $N2O$ lasers, These predictions are based on our measurements and analysis of the SMMW and IR spectra of the $V5$ band. Our heterodyne measurements on 22 SMMW laser emissions and 404 IR absorptions have been analyzed together with previous data to determine the molecular constants of the ground and $V5$ states. We made SMMW heterodyne measurements by beating the optically pumped laser radiation against harmonics of a phase-locked 35-GHz klystron. We made IR heterodyne measurements by beating diode laser radiation centered on a molecular absorption against radiation from a $CO2$ laser. Expressions theat included $\ell$-doubling and centrifugal distortion effects to the eighth power in J and K were used to fit to the data of the ground and excited states simultaneously. The effective best-fit molecular constants were obtained. Since these molecular constants were determined in large part from heterodyned data that were well calibrated with respect to absolute frequency standards, and since the frequencies of many of the various isotopic lines of $CO2$ and $N2O$ are also well known, it was straightforward to correlate these IR laser lines with the calculated IR molecular absorption spectrum to predict the resultant pure-rotational SMMW laser emissions. Most frequencies were predicted to $\sim 1MHz$ uncertainty. Energy levels for every value of $J\prime$ from 1 to 56 are pumpable with these known IR lasers, so that approximate frequencies, $V(MHz)\cong 2(j\prime +1)\times 9911.6938$, are in principle obtainable from this molecule for all $J\prime$ satisfying $1⩽J\prime ⩽56$. The predicted laser emissions are tabulated according to frequency with the corresponding pump lines, IR absorption frequencies, and intensities; the tabulation permits potential users to evaluate the merits of the various pumping schemes corresponding to a given emission frequency. Thus, the molecule $CDF3$ provides a rich choice of SMMW laser lines at approximately 20-GHz intervals from the millimeter-wave region through 1.1 THz.