Plasmonic Enhancement of Vibrational Excitations in the Infrared

Related to their size and shape, plasmonic excitations of metal particles occur in an extremely broad spectral range from visible down to radio frequencies. They can couple to other kinds of excitation with a similar energy, which in the infrared (IR) is origin of vibrational signal enhancement. In this study, we recollect main points of the current knowledge on such coupling and give examples with molecular vibrations and phonons. Plasmonic enhancement of various phononic signals gives rise to distinguish between surface enhanced IR absorption and surface enhanced IR scattering.