Linear C11 cluster: an isotopic infrared study

Carbon clusters, formed by laser ablation of graphite and deposited in argon, krypton or nitrogen matrices, have been studied by Fourier transform infrared spectroscopy. Three bands at 1942.6, 1854.8 and 1357.0 cm−1 (in N2) have been attributed to linear C11 with the aid of density functional theory (B3-LYP/6-31G*) calculations. Isotopomeric peak positions, observed after single 13C substitution in the C11 chain, were compared to predicted isotopic patterns, with excellent agreement found for the isolated weak 1357 cm−1 band. Satisfactory agreement for the two more intense, close-lying peaks has been attributed to mode mixing due to symmetry breakdown upon the introduction of 13C.