  Within our recently proposed generalized nonlocal optical response (GNOR)
model, we revisit the fundamental problem of an optically excited plasmonic
dimer. The dimer consists of two identical cylinders separated by a
nanometre-sized gap. We consider the transition from separated dimers via
touching dimers to finally overlapping dimers. In particular, we focus on the
touching case, showing a fundamental limit on the hybridization of the bonding
plasmon modes due to nonlocality. Using transformation optics we determine a
simple analytical equation for the resonance energies of the bonding plasmon
modes of the touching dimer.
