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Dr. Stefano Corni

Center S3, CNR Istituto Nanoscienze (Modena)

Tuesday, September 25th, 2012 at 11:30:00 AM  

Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)

Published on-line at 04:48:11 PM on Wednesday, September 12th, 2012

Modeling the optical properties of molecules close to metal nanoparticles

Computational modeling of Surface Enhanced Raman Scattering of molecules placed in an environment rich in metallic nanoparticles.

The optical properties of a molecule (e.g., electronic absorption cross section, Raman scattering, fluorescence) are affected by the environment where the molecule is placed. When such environment contains metallic nanoparticles, the resulting effect may be dramatic, leading often to strong signal enhancements (e.g., Surface Enhanced Raman Scattering, SERS) mainly as a consequence of the involvement in the optical processes of the nanoparticle surface plasmons.

From a computational point of view, the modeling of such phenomena are often tackled by electromagnetic approaches that approximate the molecule as a polarizable point dipole. These models provide extremely valuable insights, yet they neglect all the details of the internal structure of the molecule and require the knowledge of the intrinsic molecular optical properties, used as input parameters.

In the last years, we have developed a hybrid model that allows to couple state-of-the-art first-principle descriptions of the molecule and of its optical properties (e.g., at TDDFT level) with a continuum electromagnetic description of the metal nanoparticles and, in general, of the dielectric environment surrounding the molecule (limited to quasi-static approximation at present). In this seminar, such model will be introduced and computational applications to various metal nanoparticle-affected phenomena will be presented.

For further informations, please contact Dr. Mario Agio.