====== How to perform a calculation with implicit solvent ======

{{ :tut:solvation_models.png?nolink&600 |}}

Implicit solvation model can be added to your calculation by using [[https://github.com/henniggroup/VASPsol|VASPsol]] tool for VASP. There you can find instructions how to compile VASP with the tool and a couple of example how to use it.


==== VASPsol calculation includes the following steps: ====

  * Do a vacuum calculation for your system first and save the wavefunction file WAVECAR by specifying LWAVE = .TRUE. in the INCAR file.
  
  * Start the solvation calculation from the vacuum WAVECAR, specify ISTART = 1 in the INCAR file.

  * The solvation parameters are read from the INCAR file.
    - LSOL = .TRUE. # switch on the mode for implicit solvent
    - EB_k = N # relative permittivity of a solvent. Default value is 78.4 for water
    - Additional parameters:
      - LRHOB = .TRUE. # writes the bound charge density in the CHGCAR format into RHOB file
      - LAMBDA_D_K # the Debye length in Angstroms for using the linearized Poisson-Boltzmann model(electrolyte model)
      - TAU # surface tension parameter 


==== VASP settings for successful calculations: ====

  * ENCUT parameter should be high enough: 600 eV (for transition metal oxides) or more. PREC = .Accurate.

  * Use the all-electron potentials for H, He, Li and Be
<code>
 !------------------------------------------------------------------------
 WARNING: 
 Use all-electron pseudopotential or set CORE_C explicitly 
 for atomic-species with atomic number less than or equal to 4.
 Problem species ATOMIC NUMBER, SYMBOL & VALENCE :           3 Li
   1.00000000000000     
 I HOPE YOU KNOW WHAT YOU ARE DOING !
 !------------------------------------------------------------------------
</code>
  * NSW = None
  * LDIPOL = .FALSE.



=== Tutorial for SIMAN ===
 
[[https://nbviewer.org/github/dimonaks/siman/blob/master/tutorials/tutorial_pcm/tutorial_pcm.ipynb | Tutorial: How to perform a calculation with PCM (polarizable continuum model)]]