Infrared spectroscopic studies of hydrogenated silicon clusters - guiding the search for Si₂H_x species in the Circumstellar Envelope of IRC+10216

Silicon-bearing species Si2Hx (x = 1-6) are probable candidates in the circumstellar envelope of IRC+ 10216. We have observed several fundamentals of new silicon-containing radicals Si2H3 and Si2H5 in addition to the well-known Si2H4 and Si2H6 species from infrared spectroscopy in low temperature silane matrices at 10 K. Several infrared bands identify the Si2Hx species and can be used to search for these molecules in the circumstellar envelope of IRC+ 10216. These infrared bands are confirmed by ab initio quantum chemical calculation as well as via corresponding infrared spectra detected for the deuterated species Si2Dx