Jet-cooled laser-induced fluorescence spectroscopy of some alkoxy radicals

The laser-induced fluorescence spectra of jet-cooled alkoxy radicals were recorded. Spectra were observed for both isomers of propoxy and all three isomers of butoxy. In nearly all cases, the vibrational structure of the spectra are dominated by a C-O stretch progression, which, however, terminates much more abruptly for the primary isomers than for the more branched ones. For each of the radicals (except t-butoxy), a number of low-frequency (below the C-O stretch) vibrational modes were assigned by analogies among the alkoxy spectra and reference to frequencies from ab initio calculations. A few higher frequency modes were also assigned using similar approaches.