POSSIBLE DEVIATION OF THE SUM OF STRENGTHS FOR THE DOUBLE GIANT-DIPOLE RESONANCE FROM THE HARMONIC-OSCILLATOR LIMIT

It is shown that the part of the nuclear Hamiltonian which contains th e products of pp and hh pair operators (the scattering terms) and whic h has been usually neglected in the calculations of the giant dipole r esonance turns out to be definitely important in the study of the doub le giant dipole resonance (DGDR). The complete energy-weighted sum of strengths (EWSS) for the DGDR and a possible deviation from its value in the harmonic oscillators' limit are derived for the first time with the full nuclear Hamiltonian taken into account. The numerical calcul ations within a schematic model show an example where this deviation t urns to a strong enhancement of the EWSS for the DGDR at various parti cle numbers.