P. Kambhampati et al., ON THE ROLE OF CHARGE-TRANSFER RESONANCES IN THE CHEMICAL MECHANISM OF SURFACE-ENHANCED RAMAN-SCATTERING, Journal of the Chemical Society. Faraday transactions, 92(23), 1996, pp. 4775-4780
Citations number
27
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The surface-enhanced Raman spectrum of pyromellitic dianhydride (PMDA)
on Cu(100) is reported; it is different from that previously reported
for the Cu(lll) surface. The spectra are sensitive to the incident la
ser polarization on both surfaces but in different ways. These observa
tions are shown to be inconsistent with a simple classical picture whi
ch considers only the interaction of the surface electromagnetic field
s with the anisotropic molecular polarizability. They lend additional
support to the hypothesis that the chemical enhancement mechanism invo
lves resonance-Raman scattering via a charge-transfer intermediate sta
te. Simulations suggest that the scattering is primarily Franck-Condon
and Jahn-Teller in origin.