A New Approach to Astrophysical Spectra: The Complete Experimental Spectrum of Ethyl Cyanide (CH3CH2CN) Between 570 and 645 GHz

There is a general consensus that many of the unidentified features in astrophysical spectra are due to low lying excited vibrational and torsional states of a few molecules-commonly referred to as the astrophysical weeds. This is a challenging spectroscopic problem not only because there are many such states, but also because these states are often highly perturbed and difficult to analyze. We have previously described an alternative approach based on experimental, intensity-calibrated spectra taken at many temperatures. In this paper, we describe the procedures and results obtained with this approach for ethyl cyanide, strategies for archiving and disseminating these results, and the prospects for using these results to reduce the confusion limit in the powerful new observatories that are coming online.