A study of DFT and surface enhanced Raman scattering in silver colloids for thymine

The vibrational spectrum of crystal thymine is calculated by density functional theory (DFT) at the B3LYP complex function. Considering the effect of intermolecular H-bonds, we add two water molecules that can form H-bonds with the CO and NH groups of thymine. The experimental spectra of normal Raman of thymine in solid state and surface enhanced Raman (SERS) of thymine adsorbed in silver colloids are presented in this study. The calculated Raman spectrum of thymine by DFT is in agreement with the experimental result of normal Raman spectrum. The appearance of new bands of thymine in SERS shows that molecules of thymine are adsorbed in the surface of silver nanoparticles with a perpendicular orientation through an oxygen atom (O7).