THE LABORATORY ROTATIONAL STUDY OF METHYL ISOCYNATE

Abstract

Methyl isocyanate (CH$_{3}$NCO) is one of the most abundant species detected on the surface of the 67P/Churyumov-Gerasimenko comet.\footnote{Goesmann, F., Rosenbauer, H., Bredehoft, J.H., et al. 2015, Science, 349, aab0689.} It has also been discovered in space towards the Orion clouds where a large number of rotational lines arising from energy levels with $K \leq 3$ were reported.\footnote{Cernicharo, J., Kisiel, Z., Tercero, B., et al. 2016, A\&A, 587, L4.} In the present work, Stark-modulation spectroscopy was used to record the room temperature rotational spectrum of CH$_{3}$NCO in the spectral region from 32 to 90 GHz and to assign rotational transitions up to $K$ = 10. These new assignments were subsequently followed up to 364 GHz. Also, first laboratory measurements between 50 and 300 GHz have been performed for CH$_{3}$N$^{13}$CO and $^{13}$CH$_{3}$NCO isotopologues. Updated extensive line lists along with new sets of spectroscopic parameters provided in this work meet the needs for further detections of CH$_{3}$NCO in space