The rotational spectrum of NCCCNC in excited vibrational states

Rotational transitions of the linear molecule 3-isocyano-2-propynenitrile, NCCCNC, have been measured in the frequency range from 75 up to 120 GHz and assigned to the excited vibrational bending states (υ6 υ7 υ8 υ9)=(0002), (0003), (0004), (0011), and (0020). The analysis of the spectrum extends the spectroscopic data for NCCCNC by adding various newly determined rotational and rovibrational constants.