SPECTROSCOPIC CHARACTERIZATION OF SUPERSONIC MOLECULAR-BEAMS

A general spectroscopic method is described by which samples prepared in supersonic molecular beams can be characterized independently in th eir ground and excited electronic states. The centerpiece of this expe riment is a Fourier transform spectrometer operating at high resolutio n in the infrared, visible, and ultraviolet. This method is illustrate d with studies of the NO2 and OClO radicals prepared in supersonic mol ecular beams at temperatures and pressures characteristic of the Earth 's atmosphere. This general spectroscopic method is discussed by analo gy with low-and high-resolution studies of electronic states which in limited cases have been used to characterize sample conditions in supe rsonic molecular beam experiments.