Surface enhanced Raman scattering of ammonia

✍ Scribed by Luis A. Sanchez; John R. Lombardi; Ronald L. Birke

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 632 KB
• Volume: 108
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(84)80364-4

✦ Synopsis

A surikz cnhanccd Raman scattering (SERS) spectrum of 0.5 hi NH3 in 4.0 41 KC1 has been obscrred on a silver electrode. An approsimatc cnhancemrnt factor of 3 X IO5 is calculated, and additions evidence for the enhanced nature of rhe rpectrum is provided by the obscrvstion that totally symme~ic vibr;ttions are depolarized and by rhe strong polcnriai deprndrncc of the intensity of surface fines. AssiSnmcnts have been given to the SERS lines with the low-frequency lines assigned to il Ag-Cl and Ag-N strrtch. The positive shift of the masimum of the intcnsitp versus voltage curve Gth a lower laser cscitation frequency is tskcn as evidence for the occurrence of a charge transfer process from ammonia to the silver clcctrode. The fact that the SERS spectrum of NH3 on Ag ctn only be observed at large electrolyte concentrations is attributed to the breaking of hydrogen bonding a~ the electrode-solution interface.