i have done IR and Raman of an organic compound. Since its Raman singals were weak i conjugated it with nanoparticles and observed an SERS affect. Though some peaks in the SERS spectra were greatly enhanced, others were suppressed; this is explained by the orientation of the bonds of molecule on the NP. but what i found was in the IR spectra of the compound+NP, some peaks are merging together or broadening and those are opposite to the peaks suppressed in the Raman. Can anyone explain this or provide some literature reference for this??