What does a Raman spectrometer do?
Raman Spectroscopy is a non-destructive chemical analysis technique which provides detailed information about chemical structure, phase and polymorphy, crystallinity and molecular interactions. It is based upon the interaction of light with the chemical bonds within a material.
How does resonance Raman spectroscopy work?
It works by exciting the analyte with incident radiation corresponding to the electronic absorption bands. This causes an augmentation of the emission up to a factor of 106 in comparison to non-resonance Raman.
What is dispersive Raman spectrometer?
Dispersive Raman, as its name suggests uses a diffraction grating spectrometer (essentially operating like a prism) to disperse the light scattered from a sample and then will detect this upon a multi-channel detector such as a CCD. The wavelengths of light detected are the Raman spectrum.
What is Stokes and Antistokes lines?
Stokes lines are of longer wavelength than that of the exciting radiation responsible for the fluorescence or Raman effect. Thus, anti-Stokes lines are always of shorter wavelength than that of the light that produces them.
What does Raman spectroscopy use to identify substances?
Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down.
What are the two methods of excitation of the samples in Raman Spectroscopy?
(i) We found that the accuracy of our Raman system lies within the range ±2 cm−1. (ii) During our experiment, we used mostly two different excitation sources: Diode laser with wavelength at 782 nm and Argon-Ion laser with excitation wavelength at 514.5 nm.
What does FWHM tell you in Raman Spectroscopy?
Finally, full width at half maximum (FWHM) is a reflection of the structural distribution. Thus, for exactly the same molecule, crystalline material shows sharper Raman line than the amorphous material.
What are the types of Raman spectroscopy?
There are now more than 25 different types of known Raman spectroscopy techniques, such as spontaneous Raman, hyper-Raman scattering, Fourier transform Raman scattering [5], Raman-induced Kerr effect spectroscopy [6] and stimulated/coherent Raman scattering [1].
What is Raman effect and what is its importance?
Raman effect is the inelastic scattering of a photon by molecules which are excited to higher vibrational rotational energy levels. Raman effect explained the reason for blue colour of sea and space.
What do you need to know about Raman spectroscopy?
What is Raman Spectroscopy? Raman spectroscopy is an analytical technique where scattered light is used to measure the vibrational energy modes of a sample.
Who was the first person to observe Raman scattering?
It is named after the Indian physicist C. V. Raman who, together with his research partner K. S. Krishnan, was the first to observe Raman scattering in 1928. 1 Raman spectroscopy can provide both chemical and structural information, as well as the identification of substances through their characteristic Raman ‘fingerprint’.
Why is the Raman scatter wavelength impractical to compare?
Raman Shift. It is clear from the above, that the wavelength of the Raman scattered light will depend on the wavelength of the excitation light. This makes the Raman scatter wavelength an impractical number for comparison between spectra measured using different lasers. The Raman scatter position is therefore converted to a Raman shift away
Which is more intense Stokes or anti Stokes Raman scatter?
As a result, the Stokes Raman scatter is always more intense than the anti-Stokes and for this reason, it is nearly always the Stokes Raman scatter that is measured in Raman spectroscopy. Figure 2 Jablonski Diagram showing the origin of Rayleigh, Stokes and Anti-Stokes Raman Scatter