Abstract.
The use of principal components as a basis for a graphical procedure to analyze polar tensor data is proposed. Molecular orbital and experimental polar tensor data for all possible sign combinations of the dp/dQ_j of CHCl₃ and CDCl₃ are represented graphically as principal component scores facilitating sign selection for the dp/dQ_j. The graphs are particularly useful in analyzing an apparent conflict in dp/dQ_j sign choices based on the isotopic invariance criterion and molecular orbital results for the A1 symmetry species of these molecules. The numerical impacts of individual sign ambiguities for the dp/dQ_j on the polar tensor data are measured by the variances associated with the principal components. Assuming the dp/dQ_j sign sets with indeterminate signs provide replicated results for the polar tensor elements, their errors are estimated and compared with errors obtained previously by propagating intensity uncertainties through the polar tensor equations.
 

Keywords.
 

Keywords Plus.
Vibrational Intensities; Infrared Intensities; Substituted Methanes.