PHOTOACOUSTIC VIBRATION-ROTATION OVERTONE SPECTRUM OF THE 4-NU(1) BAND SYSTEM OF MONOBROMOACETYLENE

A high-resolution vibration-rotation overtone spectrum of natural mono bromoacetylene (HCCBr) has been recorded with a titanium:sapphire ring laser spectrometer in the wave number region 12520-12840 cm(-1). The main band assigned as 4 nu(1), its accompanying hot bands and some ove rtone bands have been rotationally analysed. Altogether nine vibration al bands belonging to the (HCCBr)-Br-79 and eleven bands belonging to the (HCCBr)-Br-81 isotopic species have been observed. Vibrational ass ignments for most of the vibrational bands have been obtained by emplo ying a simple Fermi resonance model based on normal coordinates.