$negfacousticphonon

$negfacousticphonon is the command to setup the related parameters of acoustic phonon scattering.
The equation of acoustic phonon scattering:

$W_{ac}(k)=\frac{2\pi k_{B}T}{\hslash \rho {\nu }_{ac}^2}{D}_{ac}{I}_{if}{N}_{1D}(E_k)$

Example:

$negfacousticphonon
$D_{ac}$ ${\nu }_{ac}$

$negfacousticphonon
1.248e-18 5.22e3
# Dac vac