2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227689We consider the energy weighted sums (EWS) for isovector giant dipole resonances (IVGDR) in finite nuclei within Landau kinetic theory. The dependence of both IVGDR energy, $E_{IVGDR}$, and the EWS enhancement factor, $κ(A)$, on the mass number $A$ occurs because of the boundary condition on the moving nuclear surface. The values of $E_{IVGDR}A^{1/3}$ and $κ(A)$ increase with $A$. The obtained value of the enhancement factor is about 10% for light nuclei and reaches approximately 20% for heavy nuclei. A fit of the enhancement factor to the proper experimental data provides a value for the isovector Landau amplitude of $F'_1\simeq 1.1$.14 pages, 3 figures, revised version, published in Phys. Rev. C79, 024321 (2009)Nuclear Theorytext