Negative absorption peak in FTIR

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SUMMARY

The discussion centers on the phenomenon of negative absorption peaks observed in UV-Vis absorption graphs, specifically in the context of FTIR spectroscopy. It is established that negative peaks can occur when the background signal, influenced by water and CO2, becomes stronger than the actual sample signal due to their decreasing densities during the experiment. This highlights the importance of accurate background subtraction in IR spectroscopy to avoid misinterpretation of results.

PREREQUISITES
  • Understanding of FTIR spectroscopy principles
  • Knowledge of UV-Vis absorption techniques
  • Familiarity with background signal subtraction methods
  • Basic concepts of molecular absorption and transmission
NEXT STEPS
  • Research methods for effective background subtraction in FTIR spectroscopy
  • Learn about the impact of environmental factors on UV-Vis absorption readings
  • Explore advanced techniques for analyzing negative absorption peaks
  • Study the role of water and CO2 in spectroscopic measurements
USEFUL FOR

Researchers, chemists, and spectroscopists involved in analytical chemistry and material characterization who seek to understand and interpret absorption spectra accurately.

physiks2011
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What does it mean if one found negative absorption in uv-vis absorption graph?
 
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Hi,
I have heard this explanation:
in IR spectroscopy you have to subtract signal due to water and CO2 and if their densities decrease in the course of experiment, your background which you want to subtract may become stronger than the actual background. Then you get negative peaks.
Jano
 
Something are exciting over the UV illumination processes.
 

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