Interpreting UV absorption spectra

In summary, the conversation discusses the investigation of the band gap of certain nanocrystallites using a Shimadzu spectrometer. The spectra contain additional peaks, which may be due to transitions to defects and impurities. The literature only reports smooth curves for similar work, leading to questions about the removal of peaks or the use of non-linear regression in data analysis. However, it is unlikely that researchers would remove peaks without mentioning it in their publications, and there may be other factors at play such as differences in material preparation or spectral windows.
  • #1
nana_yaw
1
0
hello all

i'm investigating the band gap of certain nanocrystallites in the powder form, using a Shimadzu spectrometer with the powder dissolved in ethanol. The spectra, however, come with several peaks in addition to the expected peak for absorption. This is not unexpected as transitions to defects and impurities should arise. What i don't understand is that the literature only reports smooth curves for similar work...!

is it that the other peaks are removed, or a non-linear regression is used to analyze the data?

please help?

nana_yaw
 
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  • #2
It is very unlikely (and unethical) that researchers would have removed peaks from their data in a publication and not mentioned it. Without seeing the references in question, it is impossible to tell for sure what is happening, but some explanations include: different details of material preparation leading to different properties, selecting spectral windows where the peaks in question do not appear, etc.
 

1. What is UV absorption spectroscopy?

UV absorption spectroscopy is a technique used to analyze the absorption of ultraviolet (UV) light by molecules. It is commonly used in chemistry and biochemistry to study the electronic structure of molecules and their functional groups.

2. How does UV absorption spectroscopy work?

UV absorption spectroscopy works by passing a beam of UV light through a sample containing the molecule of interest. The intensity of the light is then measured before and after it passes through the sample. The difference in intensity is used to determine the amount of light absorbed by the molecule, which is related to its electronic structure.

3. What information can be obtained from UV absorption spectra?

UV absorption spectra can provide information about the electronic transitions and functional groups present in a molecule. It can also be used to determine the concentration of a substance in a sample, as well as the purity and identity of a compound.

4. What factors can affect UV absorption spectra?

The shape and intensity of UV absorption spectra can be affected by several factors, including the type of functional groups present in the molecule, the solvent used, and the pH of the solution. Temperature and concentration can also influence the spectra.

5. How is UV absorption spectroscopy used in real-world applications?

UV absorption spectroscopy has many practical applications, including environmental monitoring, pharmaceutical analysis, and forensic science. It is also commonly used in the food and beverage industry to determine the quality and purity of products. Additionally, it is used in research and development to study the properties and behavior of new materials and compounds.

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