Some aspects of scaling the molecular quantum mechanical force field

Abstract Some aspects of the scaling method for empirical correction of theoretical quantum mechanical molecular force fields are considered. These are: (i) simultaneous scaling of the kinematic coefficient matrix and the force constant matrix, (ii) dependence of the force field, vibrational frequencies and modes on the scale factor matrix and (iii) the upper and lower estimations of derivatives of the frequencies with respect to scale factors. The conclusion is drawn that the advantages of the scaling procedure are most pronounced when it is applied to a quantum mechanical force field calculated at a level near the Hartree-Fock limit.