MODELING OF THE LONG-RANGE PART OF THE INVARIANTS OF THE INCREMENTAL PAIR POLARIZABILITY TENSOR DELTA(ALPHA)OVER-CAP

The long-range part of the incremental pair polarizability tensor DELT Aalpha can be described by reaction field theory. However, calculation of DELTAalpha usually requires complete knowledge of the static linea r dipole and higher polarizabilities as well as of the linear and nonl inear polarizabilities at imaginary frequencies. Since especially the latter quantities are hardly available at present, a simple but succes sful approach is given for the invariants of DELTAalpha in terms of th e Cauchy moments S(-2) and S(-4), which are known for many atoms and s mall molecules with high precision from the dispersion of the mean lin ear dipole polarizability alpha(omega).