[CP2K-user] Struggling to get SCF Convergence in Cell_Opt run

[Marcella Iannuzzi]

Hi Lenard, 

I got it converging in 10 iterations.
The outer SCF with diagonalisation is useless, since there is no 
preconditioner.
With metals you need to use smearing. 
Here are some settings I used:
      ADDED_MOS 200
      &DIAGONALIZATION T
        ALGORITHM STANDARD
      &END DIAGONALIZATION
      &MIXING T
        METHOD BROYDEN_MIXING
        ALPHA 0.01
        BETA 0.5
        NBUFFER 8
      &END MIXING
      &SMEAR
        METHOD FERMI_DIRAC
        ELECTRONIC_TEMPERATURE 500
      &END SMEAR

    &XC
      &XC_FUNCTIONAL
          &LIBXC
            FUNCTIONAL XC_GGA_X_RPW86
          &END LIBXC
          &LIBXC
            FUNCTIONAL  XC_GGA_C_PBE
          &END LIBXC
      &END XC_FUNCTIONAL

      &VDW_POTENTIAL
       POTENTIAL_TYPE NON_LOCAL
        &NON_LOCAL
          CUTOFF 300
          TYPE RVV10
##          VERBOSE_OUTPUT
          KERNEL_FILE_NAME ${data}/rVV10_kernel_table.dat
        &END NON_LOCAL
      &END VDW_POTENTIAL
    &END XC

The results:

 Step     Update method      Time    Convergence         Total energy   
 Change
  
------------------------------------------------------------------------------
     1 NoMix/Diag. 0.10E-01   20.0     0.51067755      -133.2796876462 
-1.33E+02
     2 Broy./Diag. 0.10E-01   17.6     0.00064724      -136.0334243526 
-2.75E+00
     3 Broy./Diag. 0.10E-01   17.5     0.03257808      -134.7316158415 
 1.30E+00
     4 Broy./Diag. 0.10E-01   17.7     0.00019866      -133.0666478987 
 1.66E+00
     5 Broy./Diag. 0.10E-01   17.6     0.00228816      -133.1462861174 
-7.96E-02
     6 Broy./Diag. 0.10E-01   17.6     0.00032933      -133.1654553845 
-1.92E-02
     7 Broy./Diag. 0.10E-01   17.6     0.00000406      -133.1816175525 
-1.62E-02
     8 Broy./Diag. 0.10E-01   17.7     0.00009047      -133.1825852315 
-9.68E-04
     9 Broy./Diag. 0.10E-01   17.6     0.00000504      -133.1830490186 
-4.64E-04
    10 Broy./Diag. 0.10E-01   17.6     0.00000031      -133.1828944498 
 1.55E-04

  *** SCF run converged in    10 steps ***


  Electronic density on regular grids:        -44.0000000000       
 0.0000000000
  Core density on regular grids:               43.9999999999       
-0.0000000001
  Total charge density on r-space grids:       -0.0000000001
  Total charge density g-space grids:          -0.0000000001

  Overlap energy of the core charge distribution:               
0.00000001219968
  Self energy of the core charge distribution:               
-231.41335460772382
  Core Hamiltonian energy:                                     
74.19344628639691
  Hartree energy:                                             
 45.27318657026385
  Exchange-correlation energy:                               
 -21.30000506759340
  Dispersion energy:                                           
 0.06400174824714
  Electronic entropic energy:                                 
 -0.00016939092888
  Fermi energy:                                                 
0.34714684334798

  Total energy:                                             
 -133.18289444982969



Regards
Marcella

On Friday, January 22, 2021 at 6:48:12 AM UTC+1 ASSIDUO Network wrote:

> Hi there everyone, hope you've had a great week.
>
> I've been trying to run a cell optimization of bulk Au, and I am using the 
> attached input file, but I'm not getting an inner loop SCF convergence. 
> I've made many small changes, such as including/excluding OUTER_SCF,  
> changing the SCF convergence criterion, changing the number of cell 
> optimization steps, changing the number of KPoints and changing the mixing 
> method. Nothing has worked. I haven't tried a combination of the above 
> though.
>
> Do you perhaps have any suggestions to me on how to get convergence? 
> Furthermore, I would also appreciate some tips to speed up my simulations 
> (settings/flags) wise.
>
> Thanks in advance,
> Lenard 
>
>
>
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