SOME ASPECTS OF SCALING THE MOLECULAR QUANTUM-MECHANICAL FORCE-FIELD

Some aspects of the scaling method for empirical correction of theoret ical quantum mechanical molecular force fields are considered. These a re: (i) simultaneous scaling of the kinematic coefficient matrix and t he force constant matrix, (ii) dependence of the force herd, vibration al frequencies and modes on the scale factor matrix and (iii) the uppe r 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 lim it.