Barberán Falcón, NúriaPi Pericay, Martí2009-12-282009-12-2819950163-1829https://hdl.handle.net/2445/10596An Euler-Lagrange-type equation is solved to different orders for aplane metallic system perturbed by the externa! operator Q used previously in a sum-rule calculation. This approach managed to reproduce to within a few percent the multipole surface-plasmon energies. The jellium model is used for the positive ionic background and local-density functionals for the Hamiltonian. From the zeroth-order Euler-Lagrange equation a self-consistent ground-state density is obtained and used in the first-order equation to obtain the induced density. From the induced density, several aspects of the system response are considered and special attention is focused on the static polarizability.4 p.application/pdfeng(c) The American Physical Society, 1995Polarització (Electricitat)Propietats elèctriquesEstructura electrònicaEquacions de LagrangePlasmons (Física)Polarization (Electricity)Electric propertiesElectronic structureLagrange equationsPlasmons (Physics)info:eu-repo/semantics/article94887info:eu-repo/semantics/openAccess