ELC-constant potential mode

[Jiaxing Yuan]

Dear EspressoMD developers,

I have one conceptual problem with the ELC algorithm and constant potential boundary implemented in the file elc.cpp. The lines 277-281 are these:

  if (elc_params.const_pot) {

    coulomb.field_induced = gblcblk[1];

    coulomb.field_applied = elc_params.pot_diff * height_inverse;

    field_tot -= coulomb.field_applied + coulomb.field_induced;

  }

I can understand the term field_applied  represents the electric field due to the external battery, whereas the first term field_induced represents the contribution of attractive polarization charge induced on metallic interfaces. However, my question is that physically the contribution of field_induced should have been taken into account using the image charges in ELC? Is there a double-counting here? 

Thanks in advance for your clarifying!

With kind regard,

Jiaxing