## Gaussian band shape

https://doi.org/10.1351/goldbook.G02597
A band shape described by the Gaussian function: $F\left(\nu - \nu _{0}\right) = \frac{a}{\sqrt{\pi }}\ \text{e}^{-a^{2}\ (\nu - \nu _{0})^{2}}$ In this equation, $$a^{-1}$$ is proportional to the width of the band, and $$\nu _{0}$$ is the frequency of the band maximum.