- .nb files were created in Wolfram Mathematica 11.0.0.0. Their content was additionally saved as .txt files with corresponding names. They contain programs used in the creation of the paper and are a mix of text cells and code cells.
- FrequencyShift.csv contains the calculations of the change in frequency upon changing the anion. 
- ComplexFitFunctionVis was used to create the graphs of the fit function.
- FrequencyShiftCalculator contains the theoretical calculations of expected frequency shifts for the harmonic oscillator as well as phonons at different boundaries.