[CP2K-user] Convergence problem in further steps of ab initio molecular dynamics

[Mohammad Shakiba]

Dear CP2K users,

I have installed CP2K on our university cluster with intel 2019 and it 
works properly for tests. However, when I use it for ab initio molecular 
dynamics with my structure, the first 20 steps converge but the convergence 
in the next step takes too long and it does not converge. Actually, it 
becomes close to the convergence limit of 1.0E-6 (like 2.04E-6 which was 
the closest) but does not converge even in outer loops and oscillates 
between 2.0E-6 and 1.0E-4.

Can you help me find out why this happens and how can I fix it? is it 
because of my basis sets and potentials? or my structure? Is it practical 
to increase the MAX_SCF to a high number like 1000? What are the normal 
ranges for this limit?

By the way I tried both CG and DIIS but the problem still exists.

Thanks in advance.

My structure contains Pb ans S atoms -> (PbS)16. Here are some main parts 
of my attached inputs:

    BASIS_SET_FILE_NAME BASIS_MOLOPT   ! I used MOLOPT bases file
    POTENTIAL_FILE_NAME POTENTIAL          ! with GTH pseudopotentials and 
PBE functionals
    &MGRID
       CUTOFF [Ry] 400
    &END
    &QS
       METHOD GPW 
       EPS_DEFAULT 1.0E-10
       EXTRAPOLATION ASPC 
    &END
    &POISSON      
      PERIODIC NONE
      PSOLVER  MT
    &END POISSON
    &SCF                              
      SCF_GUESS ATOMIC
      MAX_SCF 400
      EPS_SCF 1.0E-6
      &OT
        PRECONDITIONER FULL_SINGLE_INVERSE
        MINIMIZER DIIS                                            ! I also 
tried CG
        LINESEARCH 3PNT
!        STEPSIZE 0.08
!        PRECOND_SOLVER INVERSE_CHOLESKY
      &END OT
      &OUTER_SCF                                                 ! Outer 
SCF loop for 10 times
        MAX_SCF 10
        EPS_SCF 1.0E-6
      &END
    &XC
      &XC_GRID
        XC_DERIV SPLINE2
        XC_SMOOTH_RHO NN50
      &END XC_GRID
      &XC_FUNCTIONAL 
         &PBE
         &END
      &END XC_FUNCTIONAL
    &END XC

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