Reinvestigation of the acetylenic C–H stretching fundamental of propyne via high resolution, optothermal infrared spectroscopy: Nonresonant perturbations to ν1

摘要: We present the high resolution spectrum of ν1 fundamental propyne near 3335 cm−1 obtained using a very warm free jet expansion in our optothermal detection spectrometer. By concentration sample expanded at low backing pressures we have been able to observe transitions for K values up K=6. The additional data available allow us reinvestigate this vibrational band. find an unusual perturbation pattern band where individual subbands (rovibrational single value) appear be completely unperturbed level precision (7.5 MHz), but subband origin orderings are perturbed through nonresonant interactions. Attempts account ordering two‐state anharmonic interaction unsuccessful indicating that perturbations multistate origin. This type origins symmetric top molecules should common feature tops with large A rotational constants....