Theoretical vibrations of carbon chains C₃, C₄, C₅, C₆, C₇, C₈, and C₉

The MBPT(2) procedure with the 6 - 31G* basis set was used to study nearly linear carbon chains. The theoretical vibrational frequencies of the molecules C₃ through C₉ are presented and, for C₃ through C₆, compared to experimental stretching frequencies and their ¹³C/¹²C isotopomers. Predictions for C₇, C₈, and C₉ stretching frequencies are calculated by directly scaling the theoretical frequencies with factors derived from the experimental-to-theoretical ratios known for the smaller molecules.