کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1236418 | 968869 | 2006 | 6 صفحه PDF | دانلود رایگان |
The surface geometry of (RS)-phenylsuccinic acid molecule was studied by analysis of the SERS spectra of aromatic dicarboxylic acid adsorbed on silver colloid surfaces. For a reliable analysis of the SERS spectrum, we also performed density functional theoretical calculations. The SERS spectral features indicated that the RSPSA molecules should bound to the silver as dicarboxylate, with a strongly tilted orientation with respect to the normal to the surface. Such a tilted orientation was presumed to occur by the simultaneous σ and π-type coordination of carboxylate groups to silver surface caused by the steric hindrance and electrostatic repulsion between the two carboxylate groups, and thereby RSPSA on silver was easily displaced with aromatic carboxylic acids. A σ-type coordination therefore seemed to be more important than a π-type coordination for aromatic carboxylic acid derivatives to assemble on a silver surface. The large enhancement of in-plane bending, out of plane bending and ring breathing modes in the surface-enhanced Raman scattering spectrum indicates that the molecule is adsorbed on the silver surface in a ‘atleast vertical’ configuration, with the ring perpendicular to the silver surface.
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 64, Issue 3, June 2006, Pages 580–585