Fig. 7

Simulated surface charge densities over the top surfaces of the NPs present in the oligomers. a-c Surface charge densities in the case of quadrumer at the blue Fano peak (710 nm), at the Fano dip (778 nm) and at the red Fano peak (876 nm); d-f Surface charge densities in the case of heptamer at the blue Fano peak (720 nm), at the Fano dip (778 nm) and at the red Fano peak (864 nm); In the plots (a)-(f), the black arrows represent the polarization of the excitation and all the dimensions are along Fig. 1a and b