Chemisorption of biomolecules on a metal surface and its role in anomalously intensive Raman scattering

Amino acids and their derivatives are used as an example to study the mechanism of enhancement of the Raman spectra of molecules adsorbed on silver hydrosols. It is shown that adsorption occurs as a result of unshared electron pairs of nitrogen and oxygen atoms in amino and carboxyl groups, as well as a result of the formation of-electron bonds between aromatic rings and adsorption centers on the surface of the metal. It is shown that only the groups of atoms in direct contact with the metal undergo enhancement, i.e., the enhancement mechanism is local in character. A model of the bonding of amino acids with the metal surface is presented.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 33–37, March, 1985.