THE COMPLETE, TEMPERATURE-RESOLVED EXPERIMENTAL SPECTRUM OF ETHYL CYANIDE (CH3CH2CN) BETWEEN 210 AND 270 GHz

This paper reports the extension of a previously reported experimental method for the identification and characterization of astrophysical weeds in millimeter and submillimeter spectra to the widely used 210-270 GHz atmospheric window. At 300 K, these spectra contain contributions from approximately 40 vibrational states in addition to the cataloged ground state. The quantum mechanical analysis of such a large number of states would be a formidable challenge due to the complex interactions among these dense vibrational states. A new heterodyne receiver-based system is reported, as well as its intensity calibration. Results are presented in the standard astrophysical catalog format as well as our previously described point-by-point format that is effective for the characterization of blends. We also describe and validate an additional spectral synthesis approach, based on the much smaller line list catalog, which is useful in the blended line limit.