Combination bands of small linear carbon clusters: an infrared isotopic study

Isotopically labeled linear carbon clusters Cn (n=5,6,7,9) have been produced by pulsed laser ablation of mixed (12C/13C) carbon pellets, deposited in Ar matrices at 12 K and studied by Fourier transform infrared spectroscopy in the ν>2200 cm−1 energy region. The resulting spectra were compared with computed isotopomer frequencies using DFT/B3LYP/cc-pVDZ level calculations. Combination bands of 12/13Cn linear clusters are assigned and used to extract the frequencies of the fundamental symmetric mode vibrations of these clusters in their electronic ground states.