NONRESONANT IONIZATION DETECTED IR SPECTROSCOPY FOR THE VIBRATIONAL STUDY IN A SUPERSONIC JET

A spectroscopic technique for the measurement of the lR transition in a supersonic jet has been developed, This spectroscopy, the nonresonan t ionization detected IR spectroscopy (NID-IR), detects the IR transit ion by selective ionization of the vibrationally excited molecule, Bec ause of the ionization detection, it has high sensitivity. Furthermore , the ionization detection allows one to observe the IR spectrum of a specific molecular species by selecting the mass of the corresponding cation, The advantage of NID-IR spectroscopy has been demonstrated by the observation of TR spectra of phenol, o-fluorophenol, acetylene and 7-azaindole in a supersonic jet, The assignments of cis and trans rot ational isomers in o-fluorophenol are also discussed.