Similarity Transference Of Molecular Parameters. I. The Atomic Polar Tensors Of Cyanoacetylene

A similarity transference procedure for the calculation of molecular parameters is proposed. The theoretical relationships between the direct transference method normally used and the proposed procedure are discussed. The importance of adequately defining the similarity models used in the transference calculations is emphasized. As an example, similarity models are constructed using the experimental and the STO-3G and 4-31G molecular orbital values of the atomic polar tensors of the HCN, C2H2, CH3CN, C4H2, CH3CCH, and C2N2 molecules. Partial least squares calculations based on these similarity models and using the STO-3G and 4-31G values of the atomic polar tensors of HC 3N result in estimates of the experimental tensors of cyanoacetylene which have about one-half or less the root mean square error of the molecular orbital values. Also the partial least squares detection of potentially unreliable estimates of polar tensor elements is illustrated. © 1986 American Institute of Physics.8584515452