$negfionizedimpurity

$negfionizedimpurity is the command to setup the related parameters of ionized impurity scattering.
The equation of ionized impurity scattering:

 $W_{imp}(k)=4\pi F(\frac{2k}{\lambda }{)}^2[\frac{1}{{\sin }^2(\frac{\theta }{2})+(\frac{\lambda }{2k}{)}^2}{]}^2$

 $F=\frac{1}{\hslash }[\frac{}{}{]}^2$