Out-of-Plane Force Constants of Benzene

The out-of-plane force constants were calculated from the out-of-plane frequencies of C6H6, C6D6, and sym.-C6H3D3 molecules with the use of the least square method recently developed. The 45 frequencies of C6H6, C6D6, sym.-C6H3D3, p-C6H4D2, p-C6H2D4, and C6H5D molecules calculated from five force constants obtained are in good agreement with the observed, with the maximum and the mean deviations of 2.8 and 1.35%, respectively.