[QE-users] [EXT] Environ and 2D slab pp.x potential

[Andreussi, Oliviero]

Dear Antonio,

Thanks for reporting this issue and for trying Environ for your simulations. I am afraid the documentation of Environ needs to be improved on the point that you report, as this is not the first time I see this question.

Environ is not coupled with the PP code. If PP is used to plot quantities that do not depend on the environment, such as the wavefunction, the density, etc., it should work fine. However, you cannot use PP to plot quantities that depend on the environment, namely the electrostatic potential. For this purpose, you can turn on the verbosity of Environ using the verbose keyword. If you set verbose = 2 (or higher) you should get some .cube files that you can use to visualize properties of the simulation cell, in particular the electrostatic potential. Cubefiles are read by many programs and can be processed relatively easily with scripts.

Don’t hesitate to let me know if you have any problem with running Environ. You may also consider joining the google group created to support Environ users, there are not too many discussions right now, but it would be nice to build a collection of known problems, solutions and suggestions. quantum-environ-users<https://groups.google.com/forum/?hl=en#!forum/quantum-environ-users> (https://groups.google.com/forum/?hl=en#!forum/quantum-environ-users)

Best,

Oliviero

Oliviero Andreussi
--
Assistant Professor
Department of Physics
University of North Texas
Email: oliviero.andreussi at unt.edu<mailto:oliviero.andreussi at unt.edu>
Phone: +1-(940)-369-5316
Skype: olivieroandreussi
Web: https://www.materialab.org

On Jul 21, 2020, at 8:42 AM, Antonio Crepaldi <antonio.crepaldi.lanza at gmail.com<mailto:antonio.crepaldi.lanza at gmail.com>> wrote:

Dear QE users and developers,

I'm currently trying to simulate a charged 2D slab embedded in water. I'm using two planar countercharges as explained in Example 5 of Environ. The computation does not have any convergence problem, however, when I plot the total electrostatic potential (plot_num=11 in pp.x) I do not get a flat potential in the vacuum region screened by the countercharges. I would expect to find a flat potential in that region and be able to use it as a reference for further calculations.
Here is my environ input

&ENVIRON
   verbose = 0
   environ_thr = 1.d0
   environ_type = 'input'
   env_electrostatic = .true.
   env_static_permittivity = 80
   env_surface_tension = 0.D0
   env_pressure = 0.D0
   env_external_charges = 2
/
&BOUNDARY
   solvent_mode = 'full'
/
&ELECTROSTATIC
   pbc_correction = 'parabolic'
   pbc_dim = 2
   pbc_axis = 3
   tol = 5.D-13
   !inner_tol = 5.D-18
/
EXTERNAL_CHARGES (bohr)
2. 0.0 0.0 -14.29 1.0 2 3
2. 0.0 0.0  14.29 1.0 2 3

 Thank you very much for your help.
Best,

Antonio Crepaldi-Lanza

--
Department of Physics "Aldo Moro"
University of Bari
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