## Lorentzian band shape

https://doi.org/10.1351/goldbook.L03628
This band shape is described by the function: $F\left(\nu - \nu _{0}\right) = \frac{1}{\pi }\ \gamma \ ((\nu - \nu _{0})^{2}+\gamma ^{2})^{-1}$ where $$\nu_{0}$$ is the mean band position, $$\gamma$$ is the half band width at half maximum, and $$F\ (\nu - \nu _{0})$$ is the @F02526@ function.