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fricke
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Why do peaks of Stokes higher than peaks of anti-Stokes in graph of absorbance unit against wave number?
Thank you for your reply!blue_leaf77 said:Because anti-Stokes typically takes place when the initial state is an excited state.
Basically yes.fricke said:Thank you for your reply!
So, anti-Stokes has lower peaks than Stokes because its initial state is an excited state where the population of electrons at excited state is lower than the grounded state? Does it make sense?
Raman Spectroscopy is a technique used in analytical chemistry to identify and analyze the chemical composition of a substance. It involves shining a laser beam onto the sample and measuring the scattered light to determine the molecular vibrations of the sample.
This phenomenon is known as the Stokes and Anti-Stokes effect. The Stokes peaks are higher because they represent the inelastic scattering of photons, where energy is lost and the scattered light has less energy than the incident light. On the other hand, the Anti-Stokes peaks represent the elastic scattering of photons, where energy is gained and the scattered light has more energy than the incident light. Since the inelastic scattering is more likely to occur, the Stokes peaks are generally more intense.
As temperature increases, the intensity of the Stokes peaks increases while the intensity of the Anti-Stokes peaks decreases. This is because as temperature increases, the thermal energy of the molecules increases, making it more likely for inelastic scattering to occur and thus increasing the intensity of the Stokes peaks.
Raman Spectroscopy can be used to identify most types of molecules, including organic and inorganic molecules, as well as gases, liquids, and solids. However, it may not be suitable for analyzing samples that are highly fluorescent or have low Raman scattering efficiency.
Raman Spectroscopy has several advantages, including its non-destructive nature, its ability to analyze samples in a variety of states (gases, liquids, solids), and its ability to provide information on both the chemical composition and molecular structure of a substance. It also requires minimal sample preparation and can be performed in real-time, making it a valuable tool for many scientific and industrial applications.