ABSTRACT
The Raman spectrum and SERS of glycine anhydride in acidic and basic media on positive silver colloids were recorded. Calculations of the vibration frequencies were performed for glycine anhydride by B3LYP at 6-31g(d) level. The assignment of Raman spectrum and SERS of glycine anhydride in acidic media were obtained with the help of calculation. It was found that the glycine anhydride is physically adsorbed on the surface of silver. The SERS of glycine anhydride is very different in acidic media from that in basic media. This seems to mean that the geometry of glycine anhydride on positive silver colloid in basic media has changed.
Subject(s)
Anhydrides/chemistry , Glycine/chemistry , Silver/chemistry , Spectrum Analysis, Raman/methods , Colloids , Hydrochloric Acid/chemistry , Hydrogen-Ion Concentration , Sodium Hydroxide/chemistryABSTRACT
A very strong surface-enhanced Raman scattering (SERS) spectrum was obtained when adding some aggregating agent such as HNO3 and NaNO3 in positive silver colloid reduced by citrate using 633 nm radiation. In aid of characterizing the SERS of this process, SERS from positive silver colloid with the addition of H2SO3, HCl, and NH3 recorded. It was found that the SERS come from the citrate when adding HNO3, NaNO3 and H2 SO3, from NH3 and citrate when adding NH3, and only from Ag-Cl when adding HCl through comparing the spectra. Furthermore, the surface layer of positive silver colloid particles could be Ag+ , and the diffusion layer could be citrate.
