Final state interaction in electromagnetic response functions

he longitudinal and transverse response functions of the inclusive quasi-elastic (e, e') scattering are calculated in a many-body approach where the Green function is expanded over the eigenfunctions of a non-hermitian optical potential. Direct and interference contributions of all the channels are included in a simple way and final-state interaction is treated consistently with the excluive (e, e'p) reaction. The response functions of 12C and 40Ca are evaluated for momentum transfers between 400 and 550 MeV/c.