SEIRAS
Surface Enhanced Infrared Absorption Spectroscopy is a variation of infrared spectroscopy where signal enhancement is achieved by functionalization of the crystal with a metal film.
The Molecules adsorbed on this metal layer show an infrared absorption which is 10-1000 times higher. This effect is calles Surface Enhanced Infrared Absorption (SEIRA) and results from the electromagnetic interactions of the incident photon field with the metal and the molecules.