An effective scaling frequency factor method for scaling of harmonic vibrational frequencies: theory and preliminary application to toluene

In this Letter, we propose a new method for scaling of harmonic vibrational frequencies named effective scaling frequency factor (ESFF) method. It uses effective scaling factors obtained through diagonal coefficients of the potential energy distribution matrix, PED, on the basis of a non-redundant natural coordinates set. The preliminary application of ESFF method at B3LYP/6-311G∗∗ level to toluene in the region 3000–400 cm−1 renders a set of selected scaled frequencies that fits the experimental values within a root mean square deviation, RMS, of 2.48 cm−1 which is better than that obtained using SQM method (RMS 3.29 cm−1).