O atom: Difference between revisions

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  Free energy of the ion-electron system (eV)       
  Free energy of the ion-electron system (eV)       
   ---------------------------------------------------
   ---------------------------------------------------
   alpha Z PSCENC = 0.27135287
   alpha Z       PSCENC =         0.27135287
   Ewald energy TEWEN = -91.92708002
   Ewald energy   TEWEN =       -91.92708002
   -Hartree energ DENC = -281.84385691
   -Hartree energ DENC   =     -281.84385691
   -exchange EXHF = 0.00000000
   -exchange     EXHF   =         0.00000000
   -V(xc)+E(xc) XCENC = 26.11948841
   -V(xc)+E(xc)   XCENC =       26.11948841
   PAW double counting = 245.99840262-247.84808825
   PAW double counting   =       245.99840262     -247.84808825
   entropy T*S EENTRO = -0.08636665
   entropy T*S   EENTRO =       -0.08636665
   eigenvalues EBANDS = -44.50008162
   eigenvalues   EBANDS =       -44.50008162
   atomic energy EATOM = 432.26319604
   atomic energy EATOM =       432.26319604
   Solvation Ediel_sol = 0.00000000
   Solvation Ediel_sol =         0.00000000
   ---------------------------------------------------
   ---------------------------------------------------
   free energy TOTEN = 38.44696648 eV
   free energy   TOTEN =       38.44696648 eV
      
      
   energy without entropy = 38.53333313  energy(sigma->0) = 38.49014980
   energy without entropy =       38.53333313  energy(sigma->0) =       38.49014980





Revision as of 15:17, 25 April 2017

O atom in a box
 1.0          ! universal scaling parameters
 8.0 0.0 0.0  ! lattice vector  a(1)
 0.0 8.0 0.0  ! lattice vector  a(2)
 0.0 0.0 8.0  ! lattice vector  a(3)
1             ! number of atoms
cart          ! positions in cartesian coordinates
 0 0 0

We are using a POSCAR file with a single atom. Sufficiently large lattice parameters are selected so that no (significant) interactions between atoms in neighbouring cells is present.

SYSTEM = O atom in a box
ISMEAR = 0  ! Gaussian smearing
Gamma-point only
 0
Monkhorst Pack
 1 1 1
 0 0 0

For atoms or molecules a single k point is sufficient. When more k-points are used only the interaction between atoms (which should be zero) is described more accurately.

Example output (stdout) for the O atom (using VASP version 5.4.1):

running on    8 total cores
distrk:  each k-point on    8 cores,    1 groups
distr:  one band on    1 cores,    8 groups
using from now: INCAR     
vasp.5.4.1 05Feb16 (build Aug 22 2016 16:46:23) complex                        
POSCAR found :  1 types and       1 ions
scaLAPACK will be used
LDA part: xc-table for Pade appr. of Perdew
POSCAR, INCAR and KPOINTS ok, starting setup
WARNING: small aliasing (wrap around) errors must be expected
FFT: planning ...
WAVECAR not read
entering main loop
N       E                     dE             d eps       ncg     rms          rms(c)
DAV:   1     0.384469664751E+02    0.38447E+02   -0.96726E+02    16   0.293E+02
DAV:   2     0.345965628955E+01   -0.34987E+02   -0.34942E+02    32   0.450E+01
DAV:   3    -0.244485866931E+00   -0.37041E+01   -0.34307E+01    16   0.308E+01
DAV:   4    -0.312557021227E+00   -0.68071E-01   -0.66914E-01    16   0.508E+00
DAV:   5    -0.313520305300E+00   -0.96328E-03   -0.96311E-03    32   0.506E-01    0.286E-01
DAV:   6    -0.314540466589E+00   -0.10202E-02   -0.17853E-03    16   0.332E-01    0.142E-01
DAV:   7    -0.314637222361E+00   -0.96756E-04   -0.22710E-04    16   0.134E-01
1 F= -.31463722E+00 E0= -.16037490E+00  d E =-.308525E+00
writing wavefunctions 

The initial charge corresponds to the charge of isolated overlapping atoms (POTCAR file). For the first 4 steps the charge remains fixed, then the charge is updated (rms(c) column)

Short explanation of the symbols in the OSZICAR and stdout file:

N iteration count
E total energy
dE change of total energy
d eps change of the eiegenvalues (fixed potential)
ncg number of optimisation steps
rms total residual vector
rms(c) charge density residual vector

Explanation of the OUTCAR file for this example:

  • Timing and energy information
   POTLOK:  cpu time    0.0878: real time    0.0877
   SETDIJ:  cpu time    0.0015: real time    0.0014
    EDDAV:  cpu time    0.0267: real time    0.0434
      DOS:  cpu time    0.0001: real time    0.0001
   --------------------------------------------
     LOOP:  cpu time    0.1165: real time    0.1346
   
eigenvalue-minimisations :    16
total energy-change (2. order) : 0.3844697E+02 (-0.9672571E+02)
number of electron      6.0000000 magnetization
augmentation part       6.0000000 magnetization
    
Free energy of the ion-electron system (eV)      
 ---------------------------------------------------
 alpha Z        PSCENC =         0.27135287
 Ewald energy   TEWEN  =       -91.92708002
 -Hartree energ DENC   =      -281.84385691
 -exchange      EXHF   =         0.00000000
 -V(xc)+E(xc)   XCENC  =        26.11948841
 PAW double counting   =       245.99840262     -247.84808825
 entropy T*S    EENTRO =        -0.08636665
 eigenvalues    EBANDS =       -44.50008162
 atomic energy  EATOM  =       432.26319604
 Solvation  Ediel_sol  =         0.00000000
 ---------------------------------------------------
 free energy    TOTEN  =        38.44696648 eV
    
 energy without entropy =       38.53333313  energy(sigma->0) =       38.49014980


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