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