Raman Spectroscopy: Understanding Intensity & Wave Number Peaks

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SUMMARY

The peaks in Raman spectroscopy graphs represent Raman-active transitions in vibrational energy states, specifically transitions involving changes in molecular polarisability. Stokes peaks occur at lower energy, while anti-Stokes peaks appear at higher energy, corresponding to transitions from ground to excited states and vice versa. For instance, illuminating a sample with 442 nm radiation results in a Raman signal detected around 460 nm, indicating the energy difference reflects the vibrational transition energy.

PREREQUISITES
  • Understanding of Raman spectroscopy principles
  • Knowledge of vibrational energy states
  • Familiarity with molecular polarisability
  • Basic concepts of photon energy and wavelength
NEXT STEPS
  • Research the principles of Raman spectroscopy in detail
  • Learn about the significance of Stokes and anti-Stokes lines
  • Explore the relationship between photon energy and molecular transitions
  • Investigate the applications of Raman spectroscopy in material science
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Researchers, chemists, and physicists interested in molecular analysis and vibrational spectroscopy, as well as students studying advanced spectroscopy techniques.

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Tell me what do the peaks in the graph show which is b/w Intensity and wave number in raman spectroscopy ?

Are the peaks due to transition from a grnd state to an exicted state or vice versa , low energy are stokes and high energy are the anti stokes one
 
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The peaks are due to Raman-active transitions in the vibrational energy states; that is, transitions where there is a variation in the polarisability of the molecule. The peaks are the pump wavelength plus/minus the energy of the vibrational transition for anti-stokes/stokes lines.

For example, if I illuminate the sample with 442 nm radiation, the Raman signal is detected around (say) 460 nm. The difference in energy between the 442 and 460 nm photons is the energy of the vibrational transition.

Claude.
 

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