Ni 111 surface high precision: Difference between revisions

From VASP Wiki
No edit summary
 
(8 intermediate revisions by 2 users not shown)
Line 1: Line 1:
{{Sur_sci}}
{{Sur_sci - Tutorial}}


== Task ==
== Task ==


Calculation of the work function of a Ni (111) surface.
Calculation of the adsorption energies and the work function of a Ni (111) surface with high precision.


== Input ==
== Input ==
Line 46: Line 46:
   {{TAGBL|LVHAR}} = .TRUE.
   {{TAGBL|LVHAR}} = .TRUE.
  #  {{TAGBL|LVTOT}} = .TRUE.
  #  {{TAGBL|LVTOT}} = .TRUE.
*Run a single point calculation for the Ni(111) clean surface at a higher cutoff (400eV), which is needed to compute the adsorption energy.
*Potentials for O and C require an energy cut-off of 400eV:
**Previous calculation for clean cannot be used as reference.
**Recalculate with same energy cut-off.


=== {{TAG|KPOINTS}} ===
=== {{TAG|KPOINTS}} ===
Line 55: Line 60:
0 0 0
0 0 0
</pre>
</pre>
== Calculation ==
=== Adsorption energies ===
*Change of cut-off lowers total energy:
**-25.732 eV (270 eV); -25.737 eV (400 eV).
**Becomes more important for larger cells.
*The adsorption energy is calculated in the following way:
**<math> E_{\mathrm{ads}} = E_{\mathrm{total}} - E_{\mathrm{clean}} - E_{\mathrm{CO}}</math>.
**<math> E_{\mathrm{ads}} = -40.829 + 25.737 + 14.835 = -0.257 </math> eV.
=== Work function ===
* We use this run also to calculate the work-function of Ni(111).
*Use p4vasp to show the planar average of the potential:
[[File:Fig Ni 111 high prec 1.png|700px]]
<!--
*The plot of the planar average of the potential for this example should look like the following:
[[File:Fig Ni 111 high prec 2.png|200px]]
-->
*Vacuum potential <math>E^{\mathrm{vac}} = 5.45</math> eV.
*Fermi level <math>\epsilon_{\mathrm{F}} = 0.224</math> eV. (from {{TAG|OUTCAR}} file).
*Work function <math> \Phi = E^{\mathrm{vac}} - \epsilon_{\mathrm{F}} = 5.23</math> eV.


== Download ==
== Download ==
[http://www.vasp.at/vasp-workshop/examples/Ni111clean_400eV.tgz Ni111clean_400eV.tgz]
[[Media:Ni111clean_400eV.tgz| Ni111clean_400eV.tgz]]
----
[[VASP_example_calculations|To the list of examples]] or to the [[The_VASP_Manual|main page]]
{{Sur_sci}}


[[Category:Examples]]
[[Category:Examples]]

Latest revision as of 13:55, 14 November 2019

Task

Calculation of the adsorption energies and the work function of a Ni (111) surface with high precision.

Input

POSCAR

 fcc (111) surface                      
   3.53000000000000     
     0.7071067800000000    0.0000000000000000    0.0000000000000000
    -0.3535533900000000    0.6123724000000000    0.0000000000000000
     0.0000000000000000    0.0000000000000000    5.1961523999999999
   Ni
     5
Selective dynamics
Direct
  0.0000000000000000  0.0000000000000000  0.0000000000000000   F   F   F
  0.3333333300000021  0.6666666699999979  0.1111111100000031   F   F   F
  0.6666666699999979  0.3333333300000021  0.2222222199999990   F   F   F
 -0.0000000000000000 -0.0000000000000000  0.3320935940210170   T   T   T
  0.3333333300000021  0.6666666699999979  0.4413539967541983   T   T   T
 
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00
  0.00000000E+00  0.00000000E+00  0.00000000E+00


INCAR

 ENMAX = 400
    
general:
  SYSTEM = clean nickel (111) surface
  ISTART = 0
  ICHARG = 2
  ISMEAR = 2 ; SIGMA = 0.2
  ALGO = Fast
  EDIFF = 1E-6
    
special:
  LVHAR = .TRUE.
#  LVTOT = .TRUE.
  • Run a single point calculation for the Ni(111) clean surface at a higher cutoff (400eV), which is needed to compute the adsorption energy.
  • Potentials for O and C require an energy cut-off of 400eV:
    • Previous calculation for clean cannot be used as reference.
    • Recalculate with same energy cut-off.

KPOINTS

K-Points
0
Monkhorst-Pack
9 9 1
0 0 0

Calculation

Adsorption energies

  • Change of cut-off lowers total energy:
    • -25.732 eV (270 eV); -25.737 eV (400 eV).
    • Becomes more important for larger cells.
  • The adsorption energy is calculated in the following way:
    • .
    • eV.

Work function

  • We use this run also to calculate the work-function of Ni(111).
  • Use p4vasp to show the planar average of the potential:

  • Vacuum potential eV.
  • Fermi level eV. (from OUTCAR file).
  • Work function eV.

Download

Ni111clean_400eV.tgz