Spec-Soot

Spec-Soot is a publicly accessible integrated database system for soot emitted from a wide range of anthropogenic and natural sources such as forest fires, volcanic eruptions, biofuel, and fossil fuel combustions, etc. This database will serve as the foundation for further studies of soot's impact on climate and human health using laser-based diagnostic techniques, chemical analyses, and images. Our ambition is to create a unique soot database with uniform metrics that will be widely used by experimentalists and modelers in the aerosol, combustion, and astrophysics communities in the future.

Our database provides information on sample originality, their burning conditions, and their properties such as morphology (particle size, graphitic domain size, fringe spacing, curvature), optical property (complex refractive index, Ångström exponent, optical band gap), chemical compositions, and functional groups. You can also find the original data including HRTEM images, spectra including Raman scattering, ultraviolet-visible (UV-Vis) absorption, X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure spectroscopy (NEXAFS).

In addition, we offer a complimentary tool called SpecAnalyser to assist experimentalists in analyzing their spectral data with efficiency and accuracy.

Spec-Soot represents our vision to enhance soot studies through the application of spectroscopic techniques and to make our research more accessible to a wider range of users and stakeholders. By doing so, we hope to contribute to the global effort to address the issues of pollution and climate change resulting from soot emissions. We are looking for financial support to realize this idea. With the funding, Spec-Soot will have its own domain: http:\\spec-soot.com which stores all our old and new data. It is also allowed data contributions from other researchers around the world.

Kim Cuong Le

Lund University, Sweden

SpecAnalyser: a GUI software of spectral analysis

Introduction

SpecAnalyzer software has been developed by Dr. Thai Pham, a beamline scientist at MAX IV synchrotron, and Asst. Prof. Kim Cuong Le at Lund University. It has been used to analyze Raman, FTIR, UV-VIS absorption spectra of soot and black carbon. A number of scientific publications have resulted from the use of SpecAnalyser [1-5].

SpecAnalyser is a graphical user interface software. It is used to decompose spectral peaks into fundamental functions including Gaussian, Lorentzian, Voigt, and BWF (Breit Wigner Fano). Users enter the type of function to fit and interactively set a range of peak position for each function. Best fit parameters and their uncertainties are saved in a .txt output file. The decomposed peaks are saved in a separated .txt file.

A screenshot of the software is shown below:

How to use the software

SpecAnalyser is rather self-explanatory. User follows steps in the left panel from top to the bottom. The steps are listed in the following order:

1. Clear existing figure by pressing "Clear figure" button.

2. Load the data by clicking "Load data" button. Data must be a ascii file.

3. Enter a range of data in the "Fitting range" textbox. User specify min and max wavelength, wavenumber.. and press "Re-plot" button. If this box is blank full data will be used.

4. Enter type of function to be fitted in the "Select Function" box. The function is indicated by its first letter, for example, G: Gaussian, L: Lorentzian, V: Voigt, B: BWF. The letter can be capital or normal letter. The letters are ordered by the appearance of the function from the left to the right of the spectrum.

5. Enter order of background function. Background is modelled by polynomial function.

6. Press "Fitting Bound" button to choose range of peak position. Once hit enter key user point cursor to the left and the right of a peak. Repeat for each peak.

7. Hit "Fit" button to do the fitting. Result is shown in the upper graph with legend. The lower graph shows the residual of the fit and the experimental data. Results are automatically saved in .txt file.

8. User can do the same fit for many data. This is done by pressing "Multiple Fit".

This software can be used to analyse any data that can be modelled with the above mentioned functions, for example, Raman, fluorescence, absorption, x-ray photoelectron spectroscopy, ...

This software is written in Matlab. User can run the binaries on their computer but they need to have Runtime Matlab engine. User should use R2020a and above. The software is provided free of charge and can be downloaded below.

References

[1] L. Gavilan et al. (2017) , Polyaromatic disordered carbon grains as carriers of the UV bump: Far-UV to mid-IR spectroscopy of laboratory analogs, Astronomy & Astrophysics, 607, A73

[2] K.C Le et al. (2019), Direct observation of aliphatic structures in soot particles produced in low-pressure premixed ethylene flames via Online Raman spectroscopy, Proc. Combust. Inst., 377, 869-876

[3] K.C. Le et al. (2019), Raman spectroscopy of mini-CAST soot with various fractions of organic compounds: Structural characterization during heating treatment from 25 °C to 1000 °C, Combustion and Flame, 219-320

[4] K.C. Le et al. (2021), Polarization effects in Raman spectroscopy of light- absorbing carbon, Journal of Raman Spectroscopy, 52, 6, 1115-1122.

[5] K.C Le et al (2022), Watching soot inception via Online Raman spectroscopy, Combustion and Flame, 236, 111817

Windows 10, 64 bit

MacOS, 64 bit

The database is sorted in the order of soot emission sources. Use the buttons below to quickly navigate to the samples that interest you. You can also use "Search" on the right corner with your keywords. Please note that this is only an initial representation of the Spec-Soot idea and is not yet ready for use. At the moment, only the "Propane" button contains content as the majority of the buttons have not yet been connected to the database. We require funding to enhance and complete this idea with further research and development.

Propane

This visualization is merely an initial representation of the Spec-Soot idea. When having funding, we will have the resources to expand our team and dedicate more time to performing research and enriching Spec-Soot, making it more useful, informative, well-organized, and attractive.