DETECTION OF THE TRANSIENT PNO MOLECULE BY INFRARED-LASER ABSORPTION-SPECTROSCOPY

The PNO molecule has been observed in the gas phase for the first time . Some 200 vibration-rotation transitions were detected in the 1760 cm (-1) region using infrared diode laser absorption spectroscopy in a lo ng path cell. Most of the lines can be assigned to the (001)<--(000) s tretching fundamental and (011)<--(010) hot band transitions. The fund amental band exhibits a perturbation at high rotational levels which l eads to a unique assignment of the rotational numbering. The effective rotational constants determined are in good agreement with ab initio predictions and the hand origin, 1756.64586(24) cm(-1), is very close to the matrix value. A tentative rotational assignment of the hot band transitions has been made which gives a band origin of 1748.388 cm(-1 ).