Cooperative phenomena in artificial solids made from silver quantum dots: the importance of classical coupling

A simple classical effective medium computation of a two-dimensional monolayer of silver 30 angstrom diameter nanocrystals was developed and compared with experimental results. Results showed that if interparticle separation is more than 10 angstroms, the linear optical response is appropriately described by the classical effective medium model. However, the classical model does not represent the drastic changes in the reflectance spectrum seen around D/2r = 1.2.