$ifimpactuseEfgradiant

$ifimpactuseEfgradiant is the command to force the program to take the electric field of electrons and holes as

$\overrightarrow{E_n}=\mathrm{\nabla }{E}_{fn}$
$\overrightarrow{E_p}=\mathrm{\nabla }{E}_{fp}$

Sometimes, this is a more reasonable approach to estimate the position of major electrons. <be><be>

For more details of impact ionization, please see $ifimpact_ion or new command $ifimpact_new