Diode-Laser Spectrum Of Hcccn Near 5mu-M

The ν3 vibration-rotation band of cyanoacetylene, HC3N, has been measured in the wavenumber range 2068 to 2095 cm-1 to an accuracy of better than ± 0.005 cm-1 using a diode laser spectrometer. The width of the observed lines is essentially limited by Doppler-broadening. The band center of the ν3 vibration is determined from the observed P- and R-branch transitions to be at 2079.30500 (58) cm-1. The rotational constant of the excited state is B′= 0.151212 (10) cm-1.