[CP2K-user] [CP2K:16409] Large value of IASD

[Gayathri Vijayakumar]

  Dear all,

I have performed a  UKS calculation with *charge set to 0 and multiplicity 
=1* (even  number of electrons in the system). I have made around 15 
attempts with UKS False, smearing on, different minimizes, preconditioners 
and all of them failed to converge the SCF. 

In one of those trials, the SCF struggled to converge and converged after 
many steps. I terminated the simulation forcefully and got the following in 
the output even for the converged SCF steps.

Integrated absolute spin density  :                              
59.3323737862
  Ideal and single determinant S**2 :                    0.000000      
29.954091

For multiplicity set to 1, the values are unrealistic indicating severe 
spin contamination and the results seem wrong.  I have attached the input 
file. Can someone please help me in mitigating this issue?

I will be very thankful for your help.

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/3e11c6e5-ee09-44e6-9f04-004fdafe04ben%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20211228/af8a038b/attachment.htm>
-------------- next part --------------
&FORCE_EVAL
  STRESS_TENSOR ANALYTICAL

  METHOD Quickstep
  &DFT
      UKS
      BASIS_SET_FILE_NAME ./BASIS_MOLOPT
      POTENTIAL_FILE_NAME ./GTH_POTENTIALS
      CHARGE 0
	MULTIPLICITY 1
    
&MGRID
      CUTOFF 600
      NGRIDS 5 
      REL_CUTOFF 60
    &END MGRID

    &QS
      METHOD GPW
      EPS_DEFAULT 1.0E-12
    &END QS

  &SCF
      SCF_GUESS ATOMIC
      EPS_SCF 1.0E-6
      MAX_SCF 2500
      
      &OT
        MINIMIZER CG
        PRECONDITIONER FULL_KINETIC
        ENERGY_GAP 0.001
        STEPSIZE 0.05
      &END
  &END SCF

        &XC
      &XC_FUNCTIONAL PBE
      &END XC_FUNCTIONAL
      &XC_GRID
        XC_DERIV  SPLINE2
        XC_SMOOTH_RHO NN50
      &END XC_GRID
      &vdW_POTENTIAL
             DISPERSION_FUNCTIONAL PAIR_POTENTIAL
             &PAIR_POTENTIAL
             TYPE DFTD3(BJ)
             CALCULATE_C9_TERM .TRUE.
             REFERENCE_C9_TERM .TRUE.
             LONG_RANGE_CORRECTION .TRUE.
             PARAMETER_FILE_NAME dftd3.dat
             REFERENCE_FUNCTIONAL PBE
             R_CUTOFF 15
             &END PAIR_POTENTIAL
      &END vdW_POTENTIAL
  &END XC
  &END DFT

&SUBSYS
 
&TOPOLOGY
            COORD_FILE 
            COORD_FILE_FORMAT XYZ
            CONN_FILE_FORMAT OFF
        &END TOPOLOGY

    &CELL
      ABC   24.555 24.555 24.555     
      ALPHA_BETA_GAMMA 90.0 90.0 90.0
      PERIODIC XYZ
      SYMMETRY CUBIC
    &END CELL

    &KIND Si
      BASIS_SET DZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q4
    &END KIND

    &KIND O
      BASIS_SET DZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q6
    &END KIND

    &KIND H
      BASIS_SET TZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q1
    &END KIND

    &KIND Al
      BASIS_SET DZVP-MOLOPT-SR-GTH
      POTENTIAL GTH-PBE-q3
    &END KIND

    &KIND Na
      BASIS_SET DZVP-MOLOPT-SR-GTH
      MAGNETIZATION  0.0
      POTENTIAL GTH-PBE-q9
    &END KIND

  &END SUBSYS

&END FORCE_EVAL
&GLOBAL
 RUN_TYPE CELL_OPT
# RUN_TYPE ENERGY
 PRINT_LEVEL MEDIUM
&END GLOBAL
&MOTION
   &CELL_OPT
    KEEP_ANGLES T
    KEEP_SYMMETRY T
   &END CELL_OPT
   &GEO_OPT         #the cell size do not change in this calculation
     OPTIMIZER  CG        
     MAX_ITER   1000
  &END GEO_OPT
&END MOTION