Enhancement of the infrared absorption from molecular monolayers with thin metal overlayers

The infrared absorption from molecular monolayers is enhanced a factor of 20 by thin metal overlayers or underlayers with use of the attenuated-total- reflection technique. The total enhancement, including contributions from the attenuated-total-reflection geometry, is almost 104. This effect is consistent with an electric field enhancement due to collective electron resonances associated with the island nature of the thin metal films. © 1980 The American Physical Society.