Cauchy function

https://doi.org/10.1351/goldbook.08229
Function y=a/(b2+x2) where a and b are constants.
Note: If x is replaced by ν~ν~0 this function yields a Lorentzian band centered at ν~0.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 653 [Terms] [Paper]