The rotational spectrum of methyl ethyl ketone in its ground vibrational state

Abstract

The molecule 2-butanone, or methyl ethyl ketone (MEK), CH3COCH2CH3, has been studied from 8GHz to 1THz using a combination of chirped-pulse Fourier transform microwave spectroscopy and direct absorption millimeter/submillimeter spectroscopy. This molecule is of interest for the field of astrochemistry because it has functional groups in common with several known interstellar molecules, and therefore could serve as a tracer of grain surface formation pathways for complex organics in interstellar clouds. The results of the spectral studies and the analysis of the ground vibrational state of methyl ethyl ketone up to 1 THz are presented here. The challenges of spectral analysis for an organic molecule with spectral complexity arising both from internal rotation and many low-lying vibrational states are discussed. The performances of several standard fitting packages are compared in terms of handling this challenging spectral analysis problem.