Diaz Fleming et al., 2009, provided the Raman spectra in solid and solution of L-cysteine and the SERS spectra of this substance using colloidal silver nanoparticles. In their Table , the SERS bands (in the same frequency ranges here considered) are given at the following wavenumbers (in cm -1 ) (in the we can see that the band at 667 cm -1 is broad and possesses two "shoulders", as in our Figure .