A Raman spectrometer includes three main components such as the laser, the sampling interface, and the spectrometer itself. A typical Raman laser will consist of different characteristics, such as a small form factor, low power consumption, narrow linewidth, a stable power output, and a stable wavelength output.

What is the instrumentation of Raman spectroscopy?

A Raman spectrometer includes three main components such as the laser, the sampling interface, and the spectrometer itself. A typical Raman laser will consist of different characteristics, such as a small form factor, low power consumption, narrow linewidth, a stable power output, and a stable wavelength output.

How does surface-enhanced Raman spectroscopy work?

SERS uses nanoscale roughened metal surfaces typically made of gold (Au) or silver (Ag). Laser excitation of these roughened metal nanostructures resonantly drives the surface charges creating a highly localized (plasmonic) light field.

What is Surface-Enhanced Resonance Raman spectroscopy?

Surface-enhanced resonance Raman scattering (SERRS) is a sensitive and selective method for the characterization of sites in biomolecules, which have an electronic transition at energy close to or coincident with the laser frequency used.

What are the bands in Raman spectroscopy?

Raman bands of nucleic acids originate from in-plane vibrations of the nucleic acid bases (adenine, guanine, cytosine, thymine and uracil) and from the furanose-phosphate backbone. In general, Raman spectra of DNA or RNA reveal structural information about base stacking and interbase hydrogen bonding interactions.

What can Raman spectroscopy detect?

Raman spectroscopy is a spectroscopic technique used to detect vibrational, rotational, and other states in a molecular system, capable of probing the chemical composition of materials.

Which of the following is used as a detector in Raman spectroscopy?

Detectors for FT–Raman FT–Raman is almost always used with NIR lasers and appropriate detectors must be used depending on the exciting wavelength. Germanium or Indium gallium arsenide (InGaAs) detectors are commonly used.

Is Raman surface sensitive?

Enhanced Raman techniques are sensitive to the surface of the fibril, and in enhanced Raman, we observed peaks not seen in diffraction-limited Raman.

Why is silver better SERS than gold?

They are easily oxidised and lose their SERS performances in a few weeks. However, gold nanoparticles have higher stability. For the ease of synthesis, gold nanoparticles are also better. On the other hand, generally silver nanostructures exhibits two-order higher SERS efficiency.

What is D band and G band in Raman Spectroscopy?

The D band corresponds to scattering from local defects or disorders present in carbon, and the G bands originates from the in-plane tangential stretching of the C−C bonds in the graphitic structure.

What is D band and G band?

The ratio of intensity of D/G bands is a measure of the defects present on graphene structure. The G band is a result of in-plane vibrations of SP2 bonded carbon atoms whereas the D band is due to out of plane vibrations attributed to the presence of structural defects.

What are Raman active modes?

The Raman shift depends on the energy spacing of the molecules’ modes. However not all modes are “Raman active” i.e. not all appear in Raman spectra. For a mode to be Raman active it must involve a change in the polarisability, α of the molecule i.e.

Which laser is commonly used in Raman spectroscopy?

The most commonly used laser wavelength in Raman spectroscopy is 785 nm which offers low fluorescence whilst retaining relatively high Raman intensity. However, for samples which suffer from large fluorescence backgrounds, such as dyes, a 1064 nm laser may be needed.

What is SERS (surface enhanced Raman spectroscopy)?

Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopy technique with sensitivity down tothesinglemoleculelevelthatprovidesfinemolecularfingerprints,allowingfordirectidentificationoftarget analytes. Extensive theoretical and experimental research, together with continuous development of

What is surface-enhanced Raman scattering?

• Surface-enhanced Raman scattering (SERS) consists in using the large local field enhancements that can exist at metallic surfaces (under the right conditions, typically by profiting from localized surface plasmon resonances) to boost the Raman scattering signal of molecules at (or close to) the surface.

What are the advantages of Raman spectroscopy?

• Raman spectroscopy provides ‘fingerprint’ of molecular bonds and crystalline structure (phonons) in dependence on environment conditions (temperature, pressure …) through non-resonance excitation of any vibrational transitions • At the same time method applications in real life are hindered by very low cross-section of Raman scattering

How does local electromagnetic field affect Raman scattering (SERS)?

Inetrmediate conclusion II • High local electromagnetic field near the plasmon nanostructures provides very high enhancement of Raman scattering (SERS) • SERS effect depends on metal-molecule affinity and resonance conditions in molecule • The highest EFis reached in random ’hot spots’, if the probe molecule has got at this ’spot’

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