Surface and volume plasmons of spheroidal metal nanoparticles

Based on the hydrodynamic approach, the spectra of the linear polarization response of a small spheroidal metal nanoparticle interacting with an external optical field is calculated taking into account the thermal motion of valence electrons and excitation of both surface and volume plasmons. Provided calculations show that the particle elongation in the field direction reduces the broadening of the surface plasmon resonant peak and that the resonances at frequencies of volume plasmons can be accompanied by strong field enhancement in the central region of the nanoparticle.