Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

The interstellar detections of isocyanic acid, methyl isocyanate, and very recently also ethyl open the question possible detection vinyl isocyanate in medium. aim this study is to extend laboratory rotational spectrum into millimeter wave region undertake a check for its presence high-mass star forming Sgr B2. was recorded frequency regions 127.5-218 285-330 GHz using Prague spectrometer. spectral analysis supported by high-level quantum-chemical calculations. We assumed local thermodynamic equilibrium compute synthetic spectra search it ReMoCA survey performed with ALMA toward B2(N). searched same source. Accurate values centrifugal distortion constants are reported ground vibrational states trans cis isocyanate. report nondetections main hot core find that at least 11 3 times less abundant than source, respectively. Although precise formation mechanism itself remains uncertain, we infer from existing astrochemical models our observational upper limit CH3NCO:C2H5NCO ratio B2(N) consistent being formed on dust grains via abstraction or photodissociation an H atom followed addition radical. dominance such process production, combined absence analogous would indicate C2H3NCO:C2H5NCO should be rather unity.