SERS
Definition
Surface-enhanced Raman scattering. A nanorough gold or silver surface enhances the Raman signal of molecules adsorbed on it by factors of 10^6 to 10^14, pushing detection down to trace and even single-molecule levels.
- Full name
- Surface-enhanced Raman scattering
- Enhancing surface
- Nanorough gold or silver
- Signal enhancement
- Roughly 10^6 to 10^14 fold
- Sensitivity limit
- Trace to single-molecule detection
Common questions
Why does the surface need to be nanorough rather than a flat metal film?+
The enhancement arises largely from localized surface plasmon resonances concentrated at nanoscale gaps and protrusions. A flat, smooth metal surface lacks these hotspots and produces little to no signal boost.
How does SERS differ from standard Raman spectroscopy in forensic use?+
Standard Raman is used on bulk or moderately concentrated samples, while SERS is reserved for trace-level analytes such as dyes, explosives residue, or drug traces where ordinary Raman signal would be too weak to detect.
Related terms
- Mutual Exclusion Rule
- For a centrosymmetric molecule (one with a centre of inversion), a vibration is either IR active or Raman active, never both. This...
- Polarisability
- The ease with which the electron cloud of a molecule deforms in an external electric field. A vibration is Raman active only...
- Raman Effect
- Inelastic scattering of monochromatic light by a molecule. The scattered photon is shifted in wavelength by an amount equal to a vibrational...
- SORS
- Spatially offset Raman spectroscopy. The collection optics are offset from the laser spot so the detector reads photons that have travelled through...
- Stokes and Anti-Stokes Lines
- Stokes lines (longer wavelength, lower energy than the laser) come from molecules starting in the ground vibrational state; anti-Stokes lines (shorter wavelength,...