Raman optical activity clusters

Fig. 8.16 Optical images of R6G covered gold clusters within the active zone n marked in Fig. 8.11 (a) Scanning confocal microscopy image (topography mode), (b) Raman/fluorescence image of the same sample area, (c) SEM image corresponding to (a) and (b). The confocal image could be retrieved within the SEM image by means of cross marking...

The vibrational signatures are drastically modified in the nanosized particles compared to the corresponding bulk structures. These modifications are revealed by a widening and position shifts of the vibrational bands. Furthermore, the structural reconstruction at the surface of nanograins and the electron-phonon interactions play a key role on the optical and vibrational properties. In this context, spectroscopic methods such as Raman and IR are suitable tools to probe the surface reconstruction and size effects through the features of the bands related to active vibration modes. The fundamental IR absorption or Raman spectra are based on rules related to dipole moments and polarizabilities of molecules. Thus, for IR technique, when clusters or molecular complexes are considered, the intensity of their characteristic bands may be calculated according to the following formulation ... 

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