A high resolution infrared double resonance technique for molecular eigenstate spectroscopy in a free jet

Abstract

An infrared double resonance technique for the study of jet-cooled polyatomics is reported which offers state selection, access to one-photon-forbidden vibrations, sub-Doppler resolution, and high sensitivity. Molecular eigenstate spectra of the propyne 2ν1 band reveal a predicted doorway state which mediates the two-stage IVR coupling mechanism.