With the energy of a single Ag nanoparticle characterized, we can now proceed to an analysis of EET in plasmonic NP assemblies. Accordingly, we can use the single Ag NP to construct a variety of NP antenna configurations, each with interparticle distances (d) varying from 5 to 0.5 Å. We define the interparticle distance as the edge-to-edge distance between the NPs, and two of the model NP waveguides are shown in Fig. . We can also construct a NP chain where the NPs "touch" each other (d = 0 Å) in which the centerto-center distance between two atoms from adjacent NPs is less than the Ag-Ag bond-forming distance (the Ag-Ag atom bond length is 3.00 Å). Note that each of these chains are extremely large systems containing a total of 440 atoms and, therefore, would be computationally prohibitive to calculate with conventional real-time TDDFT approaches.