Basis sets Triple zeta plus polarization

These comparisons, and additional comparisons with other ab initio calculations, indicate that the harmonic frequencies for benzene have not been pinned down at the 10-20 cm 1 level by the previously mentioned ab initio calculations. In order to reduce inaccuracies in the harmonic force field, we have performed relatively large scale calculations using a valence triple zeta plus polarization basis set (pVTZ) in coupled-cluster calculations with single and double excitations (CCSD). These results, as well as comparisons with previous ab initio and recent density functional (156-157) results, are described elsewhere (108). 

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