Detection of the transient PNO molecule by infrared laser absorption spectroscopy

Abstract

The PNO molecule has been observed in the gas phase for the first time. Some 200 vibration-rotation transitions were detected in the 1760cm^-1 region using infrared diode laser absorption spectroscopy in a long path cell. Most of the lines can be assigned to the (001)←(000) stretching fundamental and (011)←(010) hot band transitions. The fundamental band exhibits a perturbation at high rotational levels which leads to a unique assignment of the rotational numbering. The effective rotational constants determined are in good agreement with ab initio predictions and the band 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 1748.388cm^-1.