In localized surface plasmon resonance, the conduction electrons of a metal nanoparticle oscillate in tune with the frequency of the incident electromagnetic wave . The effect is dominated by electrons present on the surface of the particle as it is a nanostructure and surface atoms constitute a major portion of total number of atoms.
As a dipole mode is created , electric field strength nearby the particle on outside is increased but what happens inside the volume of the nanoparticle ?
For a small metallic nanoparticle , let us say 20 nm , the field (considereing a 500nmEM wave)totally penetrates the particle and the electrons of the whole particle (volume + surface ) will resonate at plasma frequency, then there will be a field gradient generated inside the particle too but inside metals , a field cannot exist.
I am a little confused in this aspect.