Knowledge Bank

Kurtz and Adamowicz, working at the $MP2/6-310\ast$ level of theory, recently predicted the structures of C7 and C9 to be slightly $bent1$. When the structures of these molecules were re-examined in the present work using larger basis sets, also treating electron correlation via MP2, they are found to be perfectly linear. Harmonic vibrational frequencies and isotopomer frequency shifts have also been calculated, and will be compared to experiment. The reliability of these frequencies and shifts will be discussed.