  The collective excitation of the conduction electrons in subwavelength
structures gives rise to the Localized Surface Plasmon(LSP). The system
consisting of two such LSPs, known as the dimer system,is of fundamental
interest and is being actively investigated in the literature. Three regimes
have been previously identified and they are the photonic regime, the strong
coupling regime and the quantum tunneling regime. In this Letter, we propose a
new regime for this intriguing systems, the intermediate regime. In this new
regime, the quasistatic approximation, which is widely used to study such LSP
systems, fails to capture the main physics: the multiple scattering of the
electromagnetic waves between the two LSPs, which significantly modifies the
properties of the resonant modes in the system. This intermediate regime
provides a new route to explore in plasmonics, where controlling both the
excited plasmon modes and the damping rates are of paramount significance.
