Understanding the Contributions of Absorbed, Transmitted and Scattered Light
Mentor 1
Carol Hirschmugl
Location
Union Wisconsin Room
Start Date
5-4-2019 1:30 PM
End Date
5-4-2019 3:30 PM
Description
Francine Foula Mitsiopoulos* (ffm@uwm.edu), Sugato Ray (sugato@uwm.edu), Ghazal Azafar (gazarfar@uwm.edu), and Dr. Carol Hirschmugl (cjhirschmugl@gmail.com), UW-Milwaukee
A common method to detect the elements present in a sample is through Fourier-Transform Infrared (FTIR) spectroscopy, which uses infrared light to excite electrons at energies that correspond to a specific element. This technique was used on potassium bromide (KBr) pellets that contained various concentrations of carbon and carbon-oxygen based materials, such as carbon black and graphite. The expected spectra obtained through FTIR absorption should show discrete peaks in intensity, which is linearly dependent on concentration. The results did not directly show this relationship; therefore, we had to consider how each parameter affects the transmittance and absorbance of the light. There were two main components that may have affected the data: particle size and scattering. To determine how particle size influences the intensity peaks, we would have to grind the carbon black and graphite to specific sizes within the micron range. This would be difficult and time consuming and would mostly likely not have a profound impact on the data. Therefore, scattering is most likely what is causing complications when analyzing the data. Scattering is a phenomenon that occurs when reflected light is split into various paths, which increases the number of peaks in the absorption band. To verify this is the cause, we will be remeasuring the pellets with new equipment that will collect the scattered light, which will hopefully cancel the noise and produce a clean absorption band.
Understanding the Contributions of Absorbed, Transmitted and Scattered Light
Union Wisconsin Room
Francine Foula Mitsiopoulos* (ffm@uwm.edu), Sugato Ray (sugato@uwm.edu), Ghazal Azafar (gazarfar@uwm.edu), and Dr. Carol Hirschmugl (cjhirschmugl@gmail.com), UW-Milwaukee
A common method to detect the elements present in a sample is through Fourier-Transform Infrared (FTIR) spectroscopy, which uses infrared light to excite electrons at energies that correspond to a specific element. This technique was used on potassium bromide (KBr) pellets that contained various concentrations of carbon and carbon-oxygen based materials, such as carbon black and graphite. The expected spectra obtained through FTIR absorption should show discrete peaks in intensity, which is linearly dependent on concentration. The results did not directly show this relationship; therefore, we had to consider how each parameter affects the transmittance and absorbance of the light. There were two main components that may have affected the data: particle size and scattering. To determine how particle size influences the intensity peaks, we would have to grind the carbon black and graphite to specific sizes within the micron range. This would be difficult and time consuming and would mostly likely not have a profound impact on the data. Therefore, scattering is most likely what is causing complications when analyzing the data. Scattering is a phenomenon that occurs when reflected light is split into various paths, which increases the number of peaks in the absorption band. To verify this is the cause, we will be remeasuring the pellets with new equipment that will collect the scattered light, which will hopefully cancel the noise and produce a clean absorption band.
