The submillimeter wave spectrum of the C4H4 isomer vinylacetylene

The submillimeter wave spectrum of the astrochemically relevant hydrocarbon molecule vinylacetylene (butenyne) has been investigated in selected frequency regions between 181 and 789 GHz covering the quantum numbers 19 # J # 87 and 0 # Ka # 23. A set of significantly improved spectroscopic parameters has been obtained which compares favourably with the related cyano compound vinyl cyanide for which a new comprehensive set of molecular parameters is also presented. The present investigation will aid radioastronomers in search for vinylacetylene in space. q 2004 Elsevier B.V. All rights reserved