[gpaw-users] Positive and negative part of the wavefunction + electrostatic potential

[Andrew Peterson]

Hi Anders,

On 10/04/2011 12:12 AM, Anders Hellman wrote:
> Thanks once again. I am already pick out the stuff.
>
> I have had a quick look at the .get_effective_potential(), however, the routine does the summing further down in the code. If you have some qucik fix I would appreciate it very much.
>
> I would need to get just the electrostatic (Coulomb) potential out, and I think that having separate handles for getting both the electrostatic and xc-poential could be useful for many other GPAW users.

The (pseudo) electrostatic potential can be pulled from GPAW with:

from ase import units
from gpaw import GPAW
calc = GPAW(...)
v = calc.hamiltonian.vHt_g * units.Hartree

It's definitely not obvious how to do that; we should add something to 
the documentation. I also agree it would be good to have a separate 
.get_...() method for pulling out the electrostatic potential.

A while ago I repeated an old Dacapo example (made originally by John 
Kitchin) that shows how the dipole correction works and how to extract 
the electrostatic potential from both codes, and compared the GPAW and 
DACAPO results. I've been meaning to put this in a form that could go on 
the GPAW website, but in the meantime I will link to a PDF I made, in a 
form inspired by Dr. Kitchin. Others will likely find it useful.

http://dl.dropbox.com/u/2530436/gpaw-users/dipole.pdf

Best,
Andy
>
>
>
> Cheers,
> Anders
>
>
> On Oct 4, 2011, at 9:03 AM, Jussi Enkovaara wrote:
>
>> On 2011-10-04 09:49, Anders Hellman wrote:
>>>> wf = calc.get_pseudo_wave_function(band=0, kpt=0)
>>>> write('wf_real.cube', atoms, data=wf.real)
>>>> write('wf_imag.cube', atoms, data=wf.imag)
>>>>
>>> Thanks, I will try this. The reason for my confusion is that I always thought that at the Gamma point the wavefuncton is real, no matter if I have several of k-points.
>> That might actually be the case, however, the wave functions have the same data
>> type for all k-points, and therefore also the type of Gamma point wf is complex,
>> the imaginary part is just zero. The code in "write" function checks only the data
>> type, and takes absolute value for complex typed data.
>>
>> Best regards,
>> Jussi
>
> _______________________________________________
> gpaw-users mailing list
> gpaw-users at listserv.fysik.dtu.dk
> https://listserv.fysik.dtu.dk/mailman/listinfo/gpaw-users

-- 
------------
Andrew Peterson
andy.peterson at stanford.edu
aap at alum.mit.edu (permanent)