A Python 3 script for (hassle-free) plotting of IR spectra from ORCA output files with peak dectection and annotation. It combines the stick spectrum with the convoluted spectrum (gaussian line shape). The full spectrum or parts of the spectrum (via matplotlib window) can be plotted.

re numpy matplotlib scipy

Start the script with:

python3 orca-ir.py filename

it will save the plot as PNG bitmap: filename-ir.png

• filename , required: filename
• -w N , optional: line width (in cm^-1) of the gaussian (default is N = 15)
• -s , optional: shows the matplotlib window
• -n , optional: do not save the spectrum
• -e , optional: export the line spectrum in a csv-like fashion; filename of the export is input filename + "-mod.dat"

There are numerous ways to configure the spectrum in the script: Check # plot config section - configure here in the script. Here, you can configure an absorption or transmittance plot for example. You can even configure the script to plot of the single gaussian functions.

The delimiter for the line spectrum export can be changed by changing the value of export_delim =.

Colors, line thickness, line styles, level of peak detection and more can be changed in the code directly.

The spectrum always starts at zero and ends at the maximum wave number. If you need only a part of the spectrum, you can start the script with:

python3 orca-ir.py filename -s

and use the matplotlib window to zoom to an area of interest and save it. The PNG file will be replaced everytime you start the script with the same output file. If you want to keep the file, you have to rename it.