Knowledge Bank

Annual coordinate calculation was carried out for these eight isotopic molecules based mainly on the experimental data reported by Bak and $Christensen.1$ A perturbation program was used and the most general quadratic valence force potential function was assumed. A six-constant potential function did reproduce very closely the 24 out-of-plane vibrations. The results agree very well with those of Scherer and $Potts.2$ A least-squares fit of the 72 calculated to the observed in-plane frequencies was obtained using a 45-constant potential function. On the basis of these calculations, the in-plane fundamental vibrational assignments of Bak and Christensen were reexamined and modified. The new assignments as well as the final set of potential functions will be presented and discussed.