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Hartree potential that may serve as an input for the PPM can be produced by various DFT codes. The calculated system should be in the lower part of the unit cell, but z coordinates of the top-most layer has to be above zero! At least 10 Ǎ of vacuum above a slab geometry has to be used. 15-20 Ă of Vacuum are recommended. Here we show examples how to produce a hartree potential, for couple of DFT codes:
Fireball
A fireball.in for creation of an fftpot.xsf file with Hartree potential with using a McWEDA functional should look like:
&OPTION basisfile = 'answer.bas' lvsfile = 'input.lvs' kptpreference = 'input.kpts' nstepf = 1 icluster = 0 itdse = 0 iqout = 1 ifixcharge = 1 ! 0 if you don't have pre-calculated atomic charges in CHARGES iquench = -1 &END &OUTPUT iwrtxsf = 1 ! print the important file iwrtden = 1 ! print the important file &END &MESH ifixg0 = 1 ! g0 = 0.0,0.0,0.0 ! do not shift the position of atoms in fftpot.xsf with respect to the answer.bas Ecut = 300.0d0 ! not really necessary, but gives grid sampling approximately 100 pm. &END
A fireball.in file for calculations with XC on a grid computations:
&OPTION basisfile = 'answer.bas' lvsfile = 'input.lvs' kptpreference = 'samplek.kpts' nstepf = 1 icluster = 0 ! 0 for PBC / 1 for cluster calculation itdse = 0 iqout = 1 ifixcharge = 0 dt = 0.5 iquench = -1 iks = 1 imcweda = 0 idogs = 0 bmix = 0.05 &END &OUTPUT iwrtxsf = 1 ! print the important file iwrtden = 1 ! print the important file &END &MESH ifixg0 = 1 ! g0 = 0.0,0.0,0.0 ! do not shift the position of atoms in fftpot.xsf with respect to the answer.bas Ecut = 300.0d0 ! not really necessary, but gives grid sampling approximately 100 pm. &END
VASP
A LOCPOT file containing the Hartree potential is produced during standart VASP run. One just have to care about a dipole correction (if necessary). The LOCPOT file has to be convert into an *.xsf file, eg. via http://theory.chm.tu-dresden.de/~jk/software.html
FHI-AIMS
