Can electrodynamic interaction between a molecule and metal dominate a continuum background in surface-enhanced Raman scattering?

A continuum background is always coincident with the Raman spectrum enhanced by metallic nanostructures and still remains elusive. Not only does it constitute a stymied mystery in the origin per se , but also it reduces the useful quantifiable range of detection based on surface-enhanced Raman scattering (SERS). We examined theoretically near-field molecule-metal interaction to reveal its contribution to the SERS background. The results show that the spectral broadening of fluorescence and Raman scattering due to a nearby metal object is insignificant compared with experimental findings. This study abnegates the role of near-field interaction in the SERS continuum background and elucidates the microscopic molecule-metal electromagnetic interaction, despite being unable to pinpoint the primary source of the SERS background. A continuum background is always coincident with the Raman spectrum enhanced by metallic nanostructures and still remains elusive.