Infrared spectroscopy of C-(HO) and C-(DO) complexes in helium droplets.

The C molecule is an important species with implications in combustion and astrochemistry, and much of the interest in this molecule is related to its interactions with other species found in these environments. We have utilized helium droplet beam techniques along with a recently developed carbon cluster evaporation source to assemble C-(HO) and C-(DO) complexes with n = 1-2 and to record their rovibrational spectra. We observe only a single isomer of the n = 1 complex, in agreement with theoretical predictions as well as data from earlier matrix isolation studies. The spectra of the n = 1 complex are consistent with the ab initio structure, which involves a nearly linear arrangement of CCC-HO atoms in the complex. The C-HO spectrum we obtain exhibits slight differences from the analogous C-DO spectrum, which we assign to a difference in linewidth between the two spectra. We have also examined the n = 2 species and obtained a structure that appears to be distinct from those observed in matrix isolation studies and, to our knowledge, has not been previously observed.