# name
Multipole response of metal spheres to q-dependent excitation operators

# metadata.dc.description.abstract[].value
We have obtained the once and thrice energy-weighted moments of the random-phase-approximation (RPA) response to q-dependent excitation operators of type 
j
L
(qr)
Y
L
0
 for metal spheres described within a spherical jellium model. These two moments, in conjunction with the Thomas-Fermi estimation of the RPA inverse energy-weighted moment, are used to study the response of these systems as a function of q. For small values of q, we recover the surface-mode systematics, whereas for large q’s the response is mainly determined by electron-hole excitations. For intermediate q values, bulk oscillations are found and their connection with the hydrodynamical-model predictions is established. In the limit of a big sphere, we have obtained an improved bulk-plasmon pole approximation for the dispersion relation which includes in a very easy way exchange and correlation effects. We have found that these corrections are not negligible. The moments of the response corresponding to a plane wave 
e
i
q
⋅
r
 are also discussed. Numerical applications to the case of Na spheres whose ground-state structure is described by models of different complexity (constant electronic density, Thomas-Fermi or Kohn-Sham) are presented.

# metadata.dc.relation.isformatof[].value
Reproducció digital del document publicat en format paper, proporcionada per PROLA i http.//dx.doi.org/10.1103/PhysRevB.41.3434

# metadata.dc.source[].value
Articles publicats en revistes (Física Quàntica i Astrofísica)

# metadata.dc.title[].value
Multipole response of metal spheres to q-dependent excitation operators