Please confirm if bulk silver or nano-silver is Raman active ? I have one published paper which gives information on Raman spectrum of pristine Silver. However, I could not find other papers on Raman-active pure silver. The published paper is :
Raman-based detection of bacteria using silver nanoparticles conjugated
with antibodies
Ghinwa Naja,* Pierre Bouvrette, Sabahudin Hrapovic and John H. T. Luong
in Analyst, 2007, 132, 679–686 | 679 by RSC.
Thanks.
Silver and gold nanoparticles, or roughened surfaces of these materials, enhance the Raman signal of molecules near them. The silver and gold themselves are not Raman-active - in other words, what you observe is not the Raman signal of silver-silver bonds but the enhancement of signals from molecules in close proximity, sometimes by many orders of magnitude. Search on "Surface-enhanced Raman" to learn more about this effect.
Thanks Catherine for your answer. However, please find attached a paper which explains Raman activity of bare silver. Please refer raman section on page-4,5 on bare silver nanoparticles. Can you shed light on this ?
In that article they assign one of the peaks (the lowest frequency, 215 cm-1) to Ag-O, most likely the others are from the vibrations of surface species. Any bulk silver vibrations would be at lower frequency than Ag-O. So the activity shown is not strictly for bare silver, but silver with oxide and/or other adsorbed species. When the authors refer to "bare" silver they most likely mean not having their species of interest on it.
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