Knowledge Bank

We have taken spectra of $CF3C\equiv CH$ in the 3 and 1.5 micron region using a optothermal detection of the absorption of a collimated molecular beam using color center lasers for excitation. We achieve resolution of 10 MHz in the fundamental and 20 MHz in the overtone region. Because of the much greater laser intensity at 1.5 microns we obtain comparable sensitivities in each region. The fundamental spectrum shows a single bright state perturbed primarily by an anharmonic resonance with one dark state. The dark state, however, appears itself to be perturbed by a much stronger Coriolis resonance for the $K=2$ states. Numerous smaller perturbations have not yet been assigned. Unperturbed subbands have been fit with a standard deviation of about 1 MHz. The overtone region shows a highly perturbed spectrum with sharp structure riding on a broader pedestal. The sharp structure is instrument limited at 20 MHz while the pedestal has a FWHM of about 600 MHz