[CP2K-user] diverging SCF wavefunction optimization for several nanocrystal-ligand systems (after they have been successfully relaxed)
Travis
polla... at gmail.com
Thu Oct 25 15:56:27 UTC 2018
Direct mixing is inefficient and the number of steps required for
convergence grows rapidly with system size. Switch from DIRECT_P_MIXING to
BROYDEN_MIXING or PULAY_MIXING to reduce the number of steps for
convergence.
See https://www.cp2k.org/_media/events:2015_cecam_tutorial:tong_qsscf.pdf
On Wednesday, October 24, 2018 at 10:34:54 AM UTC-4, kat.... at gmail.com
wrote:
> Hi,
> I have an issue with diverging SCF wavefunction optimization for 5
> different systems of silicon nanocrystals with various ligands. So far this
> has not occurred (I have successfully simulated 20 other silicon
> nanocrystals with quite complicated ligands), so it does not seem to be
> consistent issue...
>
> For silicon nanocrystal with 235 atoms in the core and surface covered
> with Sulfur I use these parameters (extract from cp2k.out for energy_force):
>
> SCF PARAMETERS
> Density guess:
> RESTART
>
> --------------------------------------------------------
> max_scf:
> 200
> max_scf_history: 0
> max_diis:
> 4
>
> --------------------------------------------------------
> eps_scf:
> 5.00E-04
> eps_scf_history: 0.00E+00
> eps_diis:
> 1.00E-01
> eps_eigval:
> 1.00E-05
>
> --------------------------------------------------------
> level_shift [a.u.]:
> 0.00
> added MOs
> 100 0
>
> --------------------------------------------------------
> Mixing method:
> DIRECT_P_MIXING
>
> --------------------------------------------------------
> No outer SCF
>
> Number of electrons:
> 1780
> Number of occupied orbitals:
> 890
> Number of molecular orbitals:
> 4875
>
> Number of orbital functions:
> 4875
> Number of independent orbital functions:
> 4875
>
> Extrapolation method: initial_guess
>
> and I get this divergence in the optimization already after 2nd step:
>
> SCF WAVEFUNCTION OPTIMIZATION
>
> Step Update method Time Convergence Total energy
> Change
>
> ------------------------------------------------------------------------------
> 1 P_Mix/Diag. 0.40E+00 4.2 0.10908716 -2354.4136559975
> -2.35E+03
> 2 P_Mix/Diag. 0.40E+00 5.0 0.44462605 -2354.4126056799
> 1.05E-03
> 3 P_Mix/Diag. 0.40E+00 5.1 0.53885704 -2354.3562265414
> 5.64E-02
> 4 P_Mix/Diag. 0.40E+00 5.0 3.07899832 -2352.5424379413
> 1.81E+00
> 5 P_Mix/Diag. 0.40E+00 5.0 33.29887563 -1891.1308608487
> 4.61E+02
> 6 P_Mix/Diag. 0.40E+00 5.3 30.17765973 4133.1886655512
> 6.02E+03
> 7 P_Mix/Diag. 0.40E+00 5.1 32.02311479 3797.3039280923
> -3.36E+02
> 8 P_Mix/Diag. 0.40E+00 5.1 31.83587407 1215.6949983041
> -2.58E+03
> 9 P_Mix/Diag. 0.40E+00 5.1 33.45037356 4635.2206528830
> 3.42E+03
> 10 P_Mix/Diag. 0.40E+00 5.1 30.96157640 2861.7052141337
> -1.77E+03
> 11 P_Mix/Diag. 0.40E+00 5.1 29.36705839 2709.3853227498
> -1.52E+02
> 12 P_Mix/Diag. 0.40E+00 5.5 31.13837241 3593.9217491598
> 8.85E+02
> 13 P_Mix/Diag. 0.40E+00 5.1 34.63292667 4412.8333731638
> 8.19E+02
> 14 P_Mix/Diag. 0.40E+00 5.1 30.85152040 4458.1077941490
> 4.53E+01
> .......
> Leaving inner SCF loop after reaching 200 steps.
>
>
> Electronic density on regular grids: -1779.9999999908
> 0.0000000092
> Core density on regular grids: 1779.9999997505
> -0.0000002495
> Total charge density on r-space grids: -0.0000002402
> Total charge density g-space grids: -0.0000002402
>
> Overlap energy of the core charge distribution:
> 0.00000002843702
> Self energy of the core charge distribution:
> -5795.76572189967919
> Core Hamiltonian energy:
> 2938.96179612088508
> Hartree energy:
> 7673.11151856082142
> Exchange-correlation energy:
> -640.40137237794443
>
> Total energy:
> 4175.90622043252006
>
> *** WARNING in qs_scf.F:479 :: SCF run NOT converged ***
>
>
> ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):
> 55520.780056994452025
>
> But the system is fully relaxed, so the SCF run converged before (for the
> GEO_OPT) - see below the relaxation cp2k.out extract:
>
> -------- Informations at step = 25 ------------
> Optimization Method = CG
> Total Energy = -2354.4137112872
> Real energy change = -0.0000012787
> Decrease in energy = YES
> Used time = 475.723
>
> Convergence check :
> Max. step size = 0.0023939758
> Conv. limit for step size = 0.0030000000
> Convergence in step size = YES
> RMS step size = 0.0003373842
> Conv. limit for RMS step = 0.0015000000
> Convergence in RMS step = YES
> Max. gradient = 0.0004156999
> Conv. limit for gradients = 0.0004500000
> Conv. in gradients = YES
> RMS gradient = 0.0000585848
> Conv. limit for RMS grad. = 0.0003000000
> Conv. in RMS gradients = YES
> ---------------------------------------------------
>
>
> *******************************************************************************
> *** GEOMETRY OPTIMIZATION COMPLETED
> ***
>
> *******************************************************************************
>
> Reevaluating energy at the minimum
>
> Number of electrons:
> 1780
> Number of occupied orbitals:
> 890
> Number of molecular orbitals:
> 890
>
> Number of orbital functions:
> 4875
> Number of independent orbital functions:
> 4875
>
> Extrapolation method: ASPC
>
>
> SCF WAVEFUNCTION OPTIMIZATION
>
> ----------------------------------- OT
> ---------------------------------------
> Minimizer : DIIS : direct inversion
> in the iterative subspace
> using 7 DIIS vectors
> safer DIIS on
> Preconditioner : FULL_KINETIC : inversion of T + eS
> Precond_solver : DEFAULT
> stepsize : 0.15000000 energy_gap :
> 0.20000000
> eps_taylor : 0.10000E-15 max_taylor :
> 4
> ----------------------------------- OT
> ---------------------------------------
>
> Step Update method Time Convergence Total energy
> Change
>
> ------------------------------------------------------------------------------
> 1 OT DIIS 0.15E+00 3.5 0.00000227 -2354.4136673140
> -2.35E+03
> 2 OT DIIS 0.15E+00 4.2 0.00000210 -2354.4136705162
> -3.20E-06
> 3 OT DIIS 0.15E+00 4.1 0.00000166 -2354.4136799605
> -9.44E-06
> 4 OT DIIS 0.15E+00 4.1 0.00000127 -2354.4136892114
> -9.25E-06
> 5 OT DIIS 0.15E+00 4.1 0.00000111 -2354.4136936860
> -4.47E-06
> 6 OT DIIS 0.15E+00 4.1 0.00000103 -2354.4136965337
> -2.85E-06
> 7 OT DIIS 0.15E+00 4.1 0.00000092 -2354.4137006183
> -4.08E-06
>
> *** SCF run converged in 7 steps ***
>
>
> Electronic density on regular grids: -1779.9999999998
> 0.0000000002
> Core density on regular grids: 1779.9999997509
> -0.0000002491
> Total charge density on r-space grids: -0.0000002490
> Total charge density g-space grids: -0.0000002490
>
> Overlap energy of the core charge distribution:
> 0.00000002843702
> Self energy of the core charge distribution:
> -5795.76572189967919
> Core Hamiltonian energy:
> 1266.52936221037999
> Hartree energy:
> 2771.64162064259563
> Exchange-correlation energy:
> -596.81896159999383
>
> Total energy:
> -2354.41370061826001
>
> ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):
> -2354.413700618260009
>
> Please, anyone has an idea what am I doing wrong?
>
> Thank you in advance for any advice...
>
> best regards
>
> Katerina (Uni Amsterdam, NL)
>
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