SURFACE-ENHANCED RESONANCE RAMAN-SCATTERING OF A THIN-FILM OF THE NONLINEAR OPTIC MATERIAL 4-(N,N-DIMETHYLAMINO)-3-ACETAMIDONITROBENZENE GROWN ON POTASSIUM ACID PHTHALATE

Raman scattering from a layer of the non-linear optic material 4-(N,N- dimethylamino)-3-acetamidonitrobenzene (DAN) deposited on a 001 cleava ge face of a potassium acid phthalate crystal and on glass were obtain ed following deposition of a coating of silver on the surface of the m aterial. By choosing different excitation and scattering geometries, a contribution from pre-resonance Raman scattering from the bulk film a nd from surface-enhanced pre-resonance Raman scattering [SER(R)S] from the film close to the silver layer can be discerned. The approximate orientation of the DAN on the crystal has the plane of the aromatic ri ng more perpendicular to tbe surface than on glass and has the nitro g roup pointing along it. Raman scattering appears to provide both vibra tional and electronic information which is sufficiently informative to give the technique potential for the study of the orientation of mole cules in thin layers of this type. (C) 1997 by John Wiley & Sons, Ltd.