ABINITIO CALCULATION OF VIBRATIONAL FORCE-FIELDS - DETERMINATION OF NONREDUNDANT SYMMETRY COORDINATES BY LEAST-SQUARE COMPONENT ANALYSIS

A general procedure is described for vibrational analysis, using an ab initio force constant matrix which is transformed into the generalized valence force field. A method using numerical least-square fitting and redundancy elimination is proposed to determine the valence-symmetry coordinates in terms of the internal coordinate displacements. The computer program was customized to simplify the data deck construction and to input most of the data directly from the GAUSSIAN 8X output file.