Nonresonant ionization detected IR spectrum of jet-cooled phenol. Ionization mechanism and its application to overtone spectroscopy

Vibrational transitions of jet-cooled phenol have been detected by nonresonant two-photon ionization due to a UV laser from 3400 to 14000 cm−1. The UV frequency dependence of the IR-UV double resonance signals is used for discussion on the mechanism of ionization. The spectrum shows a well-resolved structure due to the first to the fourth quantum of OH stretching vibrations, CH overtones and various combination vibrations. The vibrational frequency, anharmonicity and the dissociation energy of the OH stretching mode has been measured. The bandwidth of the OH overtone is found to decrease with increase in the vibrational quantum number.