Pai-H-AgNP SERS-DFT Chem Phys Lett, 2013, 586, 132-137.pdf (original) (raw)

Raman spectra and SERS of 1H-2(Phenylazo) imidazole (PaiH) adsorbed on silver nano particles are reported. Monomolecular layer is formed at a concentration of 5 Â 10 À6 M. A trans-to-cis isomerisation of PaiH is suggested by the cis-signature peak at 570 cm À1 . In absorption spectra a single p-p ⁄ band at 358 nm is observed at higher concentrations whereas the p-p ⁄ and the n-p ⁄ bands appear at 370 nm and 456 nm, respectively, at a concentration of 5 Â 10 À6 M. This is in support of the hypothesis of trans-to-cis-isomerisation with lowering of concentration. DFT calculations are shown.