Surface enhanced spectroscopy in ecological and environmental chemistry
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DOVBESHKO, Galyna, BERNATSKA, Yliya. Surface enhanced spectroscopy in ecological and environmental chemistry. In: Ecological and environmental chemistry : - 2017, Ed. 6, 2-3 martie 2017, Chișinău. Chisinau, Republic of Moldova: Academy of Sciences of Moldova, 2017, Ediția 6, p. 63.
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Ecological and environmental chemistry
Ediția 6, 2017
Conferința "Ecological and environmental chemistry 2017"
6, Chișinău, Moldova, 2-3 martie 2017

Surface enhanced spectroscopy in ecological and environmental chemistry


Pag. 63-63

Dovbeshko Galyna1, Bernatska Yliya2
 
1 Institute of Physics of the National Academy of Sciences of Ukraine,
2 National University of “Kyiv-Mohyla Academy”
 
Disponibil în IBN: 7 martie 2019


Rezumat

Small amount of the substance under study that the searchers should work with in biology, medicine, pharmacology, art, etc. imposes some restrictions on the use of traditional techniques and makes necessary specific methods. For this reason, for analysis of the samples of extremely small amount, we proposed a new approach for registering the spectra on the basis of the effect of enhancement. The enhancement of optical process by a factor 102..106 near rough surface of metal (Au, Ag, Cu, etc.) is known already for thirty years, for both optical transitions in adsorbed molecules (Raman scattering (RS) of light, luminescence, infra red (IR) absorption and the processes which do not depend on the presence of molecules on the metal surface (for example, second harmonics generation). The effect lies in an essential increase of the intensity of transition (for example, effective cross-section increases by factor 105…1012 for RS and 10-104 for IR absorption) or efficiency of the process near metal surface. The explanation of the effect is not simple and includes several mechanisms, such as: i) the increase of the electromagnetic field near rough metal surface or island metal films, ii) the increase of the dipole transition moment of the adsorbed molecules, etc. The energy is transferred from photon to local plasmon oscillations. The plasmon oscillations have resonant character, and their frequency is determined by the form of the boundary. The surface charge which emerges on the roughness causes the Coulomb returning force. The energy from plasmon vibrations is transferred to the adsorbed molecules, which causes increased molecular absorbance. The enhancement of infrared (IR) absorption by rough metallic surface is named as SEIRA (surface enhanced infra red absorption) and enhancement of RS is named as SERS (Surface enhanced Raman Scattering). Here we demonstrate and discuss different applications of SEIRA, SERS, enhanced spectroscopy in environmental study [1, 2].