N-Acetylalanine Monolayers at the Silver Surface Investigated by Surface Enhanced Raman Scattering Spectroscopy and X-ray Photoelectron Spectroscopy: Effect of Metallic Ions

摘要

Surface-enhanced Raman scattering (SERS) spectroscopy was applied to observe the process and structure of N-acetylalanine molecules self-assembled at the silver surface. SERS data show that the N-acetylalanine molecules adsorb at the silver surface through the amino group and the entire carboxyl group in a perpendicular way after a self-reorganization. Results of SERS and X-ray photoelectron spectroscopic experiments indicate that the Ce~(3+) affects the structure of monolayers because of the binding reaction between the Ce~(3+) and the carbonyl along with the amino groups in N-acetylalanine. The Ce~(3+) capped by N-acetylalanine monolayers can be removed by adding EDTA solution and the original structure of monolayers is recovered. However, the impact of K~+ on the structure of N-acetylalanine monolayers is slight and can be ignored.