Laboratory Studies on the Infrared Absorptions of Hydrogenated Carbon‐Silicon Clusters: Directing the Identification of Organometallic SiCHxSpecies toward IRC +10216

Silicon-bearing species of the molecular formula SiCH x ( x = 1-6) are plausible candidates for organometallic molecules that might be present in the circumstellar envelope of IRC +10216. Combining matrix-isolation laboratory experiments with computed vibrational spectra of these molecules, we have observed several fundamentals of the new silicon-containing radicals SiCH 3 and SiCH 5 , in addition to the well-known SiCH 4 and SiCH 6 species, via infrared spectroscopy. These bands can now be used to search for hydrogen-deficient silicon-carbon-carrying molecules in the circumstellar envelope of the carbon star IRC +10216; the column densities of these species will yield valuable clues to the formation of silicon carbide molecules (SiC), together with their aggregates and partially hydrogenated clusters in the interstellar medium.