What is the basic principle of Raman Spectroscopy?

What is the basic principle of Raman Spectroscopy?

What are the Basic Principles of Raman Spectroscopy. It is the shift in wavelength of the inelastically scattered radiation that provides the chemical and structural information. Raman shifted photons can be of either higher or lower energy, depending upon the vibrational state of the molecule under study.

What is Raman spectroscopy and where it is applied?

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.

How Raman effect is used in Raman Spectroscopy?

RAMAN SPECTROSCOPY. The Raman effect involves scattering of light by molecules of gases, liquids, or solids. The Raman effect consists of the appearance of extra spectral lines near the wavelength of the incident light. The Raman lines in the scattered light are weaker than the light at the original wavelength.

What is the sensitivity of Raman spectroscopy?

Although Raman spectroscopy is inherently a sensitive technique, previous studies using Raman to detect cervical dysplasia both in vivo and in vitro have reported a wide range of sensitivity (70–100%) and specificity (70–100%) rates.

What is the range of Raman spectroscopy?

Raman spectra can be recorded over a range of 4000–10 cm−1(10). However, Raman active normal modes of vibration of organic molecules occur in the range of 4000–400 Δcm−1.

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 the difference between IR and Raman spectroscopy?

Raman spectroscopy depends on a change in polarizability of a molecule, whereas IR spectroscopy depends on a change in the dipole moment. Raman spectroscopy measures relative frequencies at which a sample scatters radiation, unlike IR spectroscopy which measures absolute frequencies at which a sample absorbs radiation.

What light is used in Raman Spectroscopy?

The light source used in Raman spectroscopy is a laser. The laser light is used because it is a very intense beam of nearly monochromatic light that can interact with sample molecules. When matter absorbs light, the internal energy of the matter is changed in some way.

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].

Which of the following is correct for Raman Spectroscopy?

Explanation: The correct expression for the Raman shift is: \frac{1}{2πc}\sqrt{\frac{k}{μ}}. It is same as the expression for the shift in Infrared Spectroscopy. Thus, they are complementary to each other.

What is the principle of Raman spectroscopy?

• The Raman Spectroscopy Principle. When light interacts with molecules in a gas, liquid, or solid, the vast majority of the photons are dispersed or scattered at the same energy as the incident photons. This is described as elastic scattering, or Rayleigh scattering.

What is Rayleigh scattering in Raman spectroscopy?

• The Raman Spectroscopy Principle When light interacts with molecules in a gas, liquid, or solid, the vast majority of the photons are dispersed or scattered at the same energy as the incident photons. This is described as elastic scattering, or Rayleigh scattering.

What is the Raman spectroscopy for CCl4?

• CCl 4 has one of the simplest Raman Spectra but the same principle applies for all samples: Raman spectroscopy is used to measure the unique vibrational fingerprint of the sample and from that information chemical, structural and physical properties can be determined.

What is Stokes Raman scattering?

• If the molecule gains energy from the photon during the scattering (excited to a higher vibrational level) then the scattered photon loses energy and its wavelength increases which is called Stokes Raman scattering (after G. G. Stokes).