This MATLAB-based application intends to replicate the operation of a Raman spectrometer for new users, providing an environment for quick, effective instruction where users can investigate parametrization without fear of sample/instrument damage. Most importantly, this app seeks to facilitate the development of intuition regarding spectroscopic data collection best practices using MoO3/P25 as a model system.
1. Download RamanCAT.mlappinstall
2. Open MATLAB. Once opened, double click on the downloaded file.
3. A window will appear. Click on Install.
4. Click on the "APPS" tab of your MATLAB window. Then click on the drop down list. You should see the Raman App icon on the second line. Click on it.
5. The App window has now opened. Select from the "Dataset" drop-down menu the MoO3/P25. Note that (at least for now) when initially starting the app you must always select the dataset before pressing any of the other buttons. The spectrum graph is displayed for the given parameters.
6. Feel free to play around with different set of parameters. Change the values of the parameters, the spectral range, compare spectra etc. Make sure to check out the saturated plot as well (grating 1800, acquisition 100, laser intensity 100, accumulation 1).
Instructions for Uploading New Spectral Data
1. Open the Raman CAT application and navigate to the tab labelled “Upload Additional Data”.
2. In this tab, click each of the upload buttons associated with “X Data” and “Y Data” and follow the on-screen prompt to select the files containing the respective data.
a. NOTE: Please ensure that files have been formatted appropriately in .xls or .xlsx files. Loading files with improper formatting may result in the application being unable to read your files. Proper formatting can be found on the download page at www.gtsilomelekis.com/downloads .
3. Once the X and Y data files have been selected, specify a sample name
a. NOTE: Please refrain from including file delimiters such as “/” and “.” in your sample names. For example, for a 2.5wt% Pt/Al2O3 catalyst, do not use 2.5PtAl2O3 as the sample name. Instead, 2_5PtAl2O3 or 2-5PtAl2O3 would be acceptable.
4. Once an accepted sample name has been input, click finalize to automatically save the data. This should take less than 1 minute depending on the size of selected data files.
5. If successful, file paths should clear and sample name should read “Upload Successful!”
Instructions for Uninstalling Spectral Data
In the case of a faulty upload file or unwanted spectra, files can be removed directly from the application directory by the following steps:
1. Find your MATLAB directory
2. In the MATLAB directory, navigate to Add-Ons gApps gRaman App
3. Once here, you should be able to see all files that the application calls during use, including those which you wish to remove.
4. Simply find and delete the sample files you wish to remove, including X and Y data. These files will end “...NDXX.mat” and “xYYY.mat”, where XX will be 1-100 and YYY will be 1800 and 600.
Additionally, you may delete the file named “NewMaterial_Mod.mat”, which controls the sample names available in the application drop-down. One thing to consider with this action is that doing so will require re-uploading other spectral data files not packaged with the application. Therefore, if the user has uploaded multiple files, it may be better to leave this file as is and modify the contents directly in MATLAB. One may do this outside of the application by opening
Once the app is initialized, the user can bring up the provided spectra by navigating to the "Sample" bar and selecting MoO3/P25 from the drop-down list. From here, the user is free to vary the standard collection parameters changed during the course of a Raman experiment. These parameters can be changed either by using the interactive scroll bars or the arrow keys provided next to the numerical output. Special attention should be paid towards the changes observed to the signal-to-noise ratio and peak locations as parameters are changed, as these play a crucial role in spectrum analysis and the physical/chemical conclusions that can be made about a sample. Additionally, two similar conditions can be compared by first selecting the one parametrization of interest, then selecting the "Compare Spectra" box, and then inputting the new parametrization. This will plot two spectra on top of each other for a quick and detailed comparison, as changes to spectra are sometimes minor but important.
This material is based upon work supported in part by Rutgers, The State University of New Jersey, and the National Science Foundation Award #1751683.
The authors would like to sincerely thank Anastasios Dimas for his help with the app.