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events:2018_summer_school:converging_cutoff [2018/05/31 10:16]
mwatkins [Analysis]
events:2018_summer_school:converging_cutoff [2018/06/11 09:54] (current)
ibethune ↷ Page moved from exercises:2018_uol_school:converging_cutoff to events:2018_summer_school:converging_cutoff
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 This exercise is similar to the previous one, but uses a setup and system more typical of CP2K usage. We will use a system of 32 H<​sub>​2</​sub>​O water molecules within a periodic box. Here is the input template: This exercise is similar to the previous one, but uses a setup and system more typical of CP2K usage. We will use a system of 32 H<​sub>​2</​sub>​O water molecules within a periodic box. Here is the input template:
  
-<​code>​+<​code ​cp2k input_template.inp>
 &GLOBAL &GLOBAL
   PRINT_LEVEL MEDIUM   PRINT_LEVEL MEDIUM
Line 91: Line 91:
 Compared to the Si example, this is a larger system, we are using the OT optimizer in a good setup for a small to medium insulating system: Compared to the Si example, this is a larger system, we are using the OT optimizer in a good setup for a small to medium insulating system:
  
-<​code>​+<​code ​cp2k>
     &SCF     &SCF
       SCF_GUESS RESTART       SCF_GUESS RESTART
Line 109: Line 109:
 and we are also saving the forces on the atoms and we are also saving the forces on the atoms
  
-<​code>​+<​code ​cp2k>
   &PRINT   &PRINT
     &FORCES     &FORCES
Line 212: Line 212:
  
 For BLYP functional some smoothing needs to be applied. The smoothing may also converge forces more rapidly than the default settings, but at the expense of modifying the functional slightly. For BLYP functional some smoothing needs to be applied. The smoothing may also converge forces more rapidly than the default settings, but at the expense of modifying the functional slightly.
 +
 +<​note>​**TASKS**
 +
 +compare to the previous calculation,​ but using a smoothing section in the XC section.
 +
 +<​code>​
 +    &XC
 +      &​XC_FUNCTIONAL PBE
 +      &END XC_FUNCTIONAL
 +      &​XC_GRID
 +        XC_SMOOTH_RHO NN50
 +        XC_DERIV NN50_SMOOTH
 +      &END
 +    &END XC
 +</​code>​
 +  ​
 +compare the convergence of LDA and BLYP to PBE.
 +
 +<​code>​
 +&​XC_FUNCTIONAL PADE # or BLYP
 +&END XC_FUNCTIONAL
 +</​code>​
 +</​note>​
 +
 +<note tip>
 +Also change the psuedo potential to the appropriate functional.
 +<​code>​
 +    &KIND O
 +      BASIS_SET DZVP-MOLOPT-SR-GTH-q6
 +      POTENTIAL GTH-PADE-q6
 +    &END KIND
 +</​code>​
 +PADE is a synonym for LDA.
 +</​note>​
 +
events/2018_summer_school/converging_cutoff.1527761788.txt.gz · Last modified: 2018/05/31 10:16 by mwatkins