1988–89: The Year of OH-Ar

Abstract

Fluorescence excitation spectra of OH-Ar complexes are observed in the vicinity of several OH A ²∑⁺ − ²П_3/2 transitions. Intermolecular potentials derived from these spectra illustrate the dramatic change in the OH-Ar potential upon electronic excitation of the OH moiety. The OH (center-of-mass) to Ar distance is substantially reduced and Ar becomes much more tightly bound to OH. The differences in the OH-Ar potentials are also reflected in the rate of vibrational predissociation, which is at least a thousand times faster in the excited electronic state. Much smaller changes in the potentials are found upon vibrational excitation of OH, as shown in the ground electronic state by vibrational overtone spectroscopy.

Alfred P. Sloan Research Fellow and Camille and Henry Dreyfus Foundation Teacher-Scholar.