(a–d) Top view of the position of two molecules and metal blocks: the polarization direction of the incident field is represented by two-way orange arrow. (a–c) One of the molecules is fixed (red circle), while the other one (blue circle) is placed in different positions. (d) We alter the polarization direction in the same configuration as (c). (e) Absorption cross-section of the molecule (red circle) is plotted against the incident field energy for different arrangement of molecules. The black dotted line represents the absorption for the case where only one molecule (red circle) exists. One can see the large peak shift (~0.6 meV) due to the intermolecule interaction, only when both of the molecules are located in the hot spots (c, d).