Rovibronic Analysis of the Laser Induced Fluorescence Excitation Spectrum of the Jet-cooled Methoxy Radical

The laser induced fluoresence excitation spectrum for the à A1 ↔ X̃ 2E transition of the methoxy radical has been reinvestigated. An extensive set of vibrational levels has been assigned with the aid of increased vibrational and rotational cooling. Many of these vibrational assignments are confirmed by rotational analysis of bands involving both the symmetric and asymmetric fundamentals of the à state as well as vibrations containing two quanta of the e modes. Although parts of the vibrational structure have been assigned previously, several discrepancies are identified and corrected. Vibrational frequencies have been obtained for all the modes in the à A1 state of the molecule. The Fermi resonance that exists between ν3 and ν2 has been investigated and interaction constants describing it have been obtained.