Lorentzian band shape

This band shape is described by the function:

$F ν − ν 0 = 1 π γ ( ( ν − ν 0 ) 2 + γ 2 ) −1$

where $v 0$ is the mean band position, $γ$ is the half band width at half maximum, and $F ( ν − ν 0 )$ is the frequency distribution function.