[Pw_forum] Computing Vacuum potential

[Elliot Menkah]

Hello Everyone,
I'm trying to calculate the work function of a pure slab as such I'm
computing for the vacuum potential.
When I run my scf calculation and compute the vacuum potential, I get
very small values for the vacuum potential. I get a vacuum potential of
about 0.8 eV and a fermi energy of -0.234. which seems not to make sense.

Please finds attached the input file for the self consistent field(scf) 
calculation.

Could there be anything wrong with the system please.
Do I have to include or account for dipole correction? And how please.
All contributions are welcome.
Thank you.


Warm Regards,

Elliot

-- 
Elliot S. Menkah
Research Student - Computational Chemistry/ Computational Material Science
Theoretical and Computational Chemistry
Dept. of Chemistry
Kwame Nkrumah UNiversity of Sci. and Tech.
Kumasi
Ghana

Tel: +233 243-055-717

Alt Email: elliotsmenkah at gmail.com
           elliotsmenkah at hotmail.com

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&CONTROL
       title = 'Ni-1x1-100-2L-METADISE-surf-full-rlx' ,
       calculation = 'scf' ,
       restart_mode = 'from_scratch' ,
       outdir = './tmp' ,
       pseudo_dir = '/home/mmc14/pseudo' ,
       prefix = 'ni-100-1x1-2L-metaD-full-rlx',
       tstress = .true. ,
       tprnfor = .true. ,
/
 &SYSTEM
       ibrav = 0,
       celldm(1) = 1.88972599,
       nat = 4,
       ntyp = 1,
       ecutwfc = 60,
       ecutrho = 650,
       occupations='smearing',
       smearing='mp',
       degauss=0.005,
       nbnd=50,
       nspin=2,
       starting_magnetization(1)=0.5,
/
 &ELECTRONS
        conv_thr = 1.0D-6,
        mixing_mode = 'local-TF'
        mixing_beta = 0.2,
/
 &IONS
/
ATOMIC_SPECIES
        Ni 58.6934   Ni.pbe-nd-rrkjus.UPF
ATOMIC_POSITIONS (alat)
Ni       3.522092393   3.522092393   0.059971412
Ni       1.761046196   1.761046196   0.059979212
Ni       3.522092393   1.761046196   1.701070884
Ni       1.761046196   3.522092393   1.701070884
K_POINTS automatic
  5 5 1   0 0 0
CELL_PARAMETERS
 +3.5220923930  +0.0000000000  +0.0000000000
 +0.0000000000  +3.5220923930  +0.0000000000
 -0.0000000000  -0.0000000000 +15.5220923930