Quickstep: SCF Energy increasing after few outer-SCF cycles
Matt W
MattWa... at gmail.com
Wed Aug 21 18:35:29 UTC 2013
Hi,
this seems to occur in some systems, sorry no deep physical understanding
of the problem - could well be that your geometry is not ideal / nearly
metallic electronic structure. A sure sign is that the electron density
projected onto the RS grid starts to get (significantly - losing noticable
numbers of electrons) worse as the calculation goes on.
FULL_ALL preconditioner is quite aggressive - pragmatically try switching
to FULL_SINGLE_INVERSE for an ENERGY calculation until (very nearly)
converged, then go back to FULL_ALL. The speed gains (in SCF cycles) are
probably only worth it for long MD runs anyway.
Matt
On Wednesday, August 21, 2013 2:54:12 PM UTC+1, Sharma SRK Chaitanya
Yamijala wrote:
>
> Dear all CP2K users,
>
> I am trying to optimize a Graphene Quantum Dot using BLYP-DFT-D3/DZVP
> method as implemented in CP2K. While optimizing I have observed that, SCF
> energy is decreasing (i.e. becoming more negative) at the beginning of the
> run, but after few outer-SCF loops, the energy starts increasing and the
> increment is going on and on if I am leaving the system to run.
>
> Also, I have observed that the inner-SCF energy has reached a convergence
> (for this system) value of ~ 10^(-5) after 2 outer-SCF cycles (where my
> EPS_SCF is 1.0E-6) and after the beginning of the 3rd outer-SCF tolerance
> has increased to a value of ~ 10^(-3).
>
> I would like to get your suggestions on any way to avoid this convergence
> issue. The input file and the output file (just before and after the 2nd
> outer-SCF) are given below (hopping they may be help you in suggesting).
>
> Thank you all,
> Sincerely,
> Sharma.
>
> P.S: I have checked in the mailing list but I couldn't exactly found any
> post on this issue (though there are on BOMD-energy increment etc.)
>
> *Input_file:*
>
> &FORCE_EVAL
>
> METHOD Quickstep
>
> &DFT
>
> CHARGE = 0
> MULTIPLICITY = 2
> LSD # for odd number of electrons and specifying this keyword itself
> enforces for spin-polarized calculations
>
> BASIS_SET_FILE_NAME BASIS_MOLOPT
> POTENTIAL_FILE_NAME GTH_POTENTIALS
>
> &MGRID
> CUTOFF 320
> NGRIDS 5
> REL_CUTOFF 40
> &END MGRID
>
> &QS
> METHOD GPW
> EPS_DEFAULT 1.0E-10
> &END QS
>
> &SCF
>
> SCF_GUESS RESTART
> EPS_SCF 1.0E-6
> MAX_SCF 100
>
> &OUTER_SCF
> EPS_SCF 1.0E-6
> MAX_SCF 500
> &END
>
> &OT
> MINIMIZER CG
> PRECONDITIONER FULL_ALL
> ENERGY_GAP 0.001
> STEPSIZE 0.05
> &END
>
> &END SCF
>
> &XC
>
> &XC_FUNCTIONAL BLYP
> &END XC_FUNCTIONAL
>
> &XC_GRID
> XC_DERIV SPLINE2
> XC_SMOOTH_RHO NN50
> &END XC_GRID
>
> &vdW_POTENTIAL
>
> DISPERSION_FUNCTIONAL PAIR_POTENTIAL # POTENTIAL_TYPE is alias to
> DISPERSION_FUNCTIONAL
>
>
> &PAIR_POTENTIAL
> TYPE DFTD3
> PARAMETER_FILE_NAME dftd3.dat
> REFERENCE_FUNCTIONAL BLYP
> &END PAIR_POTENTIAL
>
> &END vdW_POTENTIAL
>
> &END XC
>
> &POISSON
> POISSON_SOLVER WAVELET
> PERIODIC NONE
> &END POISSON
>
> &END DFT
>
> &SUBSYS
>
> &CELL
> ABC 38.0 38.0 38.0
> ALPHA_BETA_GAMMA 90.0 90.0 90.00
> PERIODIC NONE
> &END CELL
>
> &TOPOLOGY
> &CENTER_COORDINATES
> &END
> &END
>
> &COORD
> @INCLUDE gqd_270.xyz
> &END COORD
>
> &KIND H
> BASIS_SET DZVP-MOLOPT-SR-GTH
> POTENTIAL GTH-BLYP-q1
> &END KIND
>
> &KIND C
> BASIS_SET DZVP-MOLOPT-SR-GTH
> POTENTIAL GTH-BLYP-q4
> &END KIND
>
> &KIND N
> BASIS_SET DZVP-MOLOPT-SR-GTH
> POTENTIAL GTH-BLYP-q5
> &END KIND
>
> &END SUBSYS
>
> &END FORCE_EVAL
>
> &GLOBAL
> PROJECT au20_tetra_on_n-gqd
> RUN_TYPE GEO_OPT
> PRINT_LEVEL MEDIUM
> &END GLOBAL
>
> &MOTION
> &GEO_OPT
> OPTIMIZER BFGS
> MAX_ITER 5000
> MAX_FORCE 1.00D-4
> TYPE MINIMIZATION
> &END
>
> &END MOTION
>
>
> ###########################################################################################################################
> *
> *
> *OUTPUT-FILE:*
>
>
> 98 OT LS 0.54E-01 6.9 -1982.8376246687
>
> Trace(PS): 1174.9999638412
> Electronic density on regular grids: -1174.9999638398
> 0.0000361602
> Core density on regular grids: 1174.9999998887
> -0.0000001113
> Total charge density on r-space grids: 0.0000360489
> Total charge density g-space grids: 0.0000360489
>
> 99 OT CG 0.54E-01 12.3 0.00000845 -1982.8383595833
> -7.61E-05
>
> Trace(PS): 1174.9999635922
> Electronic density on regular grids: -1174.9999635907
> 0.0000364093
> Core density on regular grids: 1174.9999998887
> -0.0000001113
> Total charge density on r-space grids: 0.0000362980
> Total charge density g-space grids: 0.0000362980
>
> 100 OT LS 0.22E+00 6.9 -1982.8383813757
>
> *** SCF run NOT converged ***
>
>
> Electronic density on regular grids: -1174.9999635907
> 0.0000364093
> Core density on regular grids: 1174.9999998887
> -0.0000001113
> Total charge density on r-space grids: 0.0000362980
> Total charge density g-space grids: 0.0000362980
>
> Overlap energy of the core charge distribution:
> 0.00005046108667
> Self energy of the core charge distribution:
> -4271.91259980407449
> Core Hamiltonian energy:
> 1351.88408937624945
> Hartree energy:
> 1448.17384258600623
> Exchange-correlation energy:
> -510.06161737575133
> Dispersion energy:
> -0.92214661917833
>
> Total energy:
> -1982.83838137566136
>
> outer SCF iter = 3 RMS gradient = 0.84E-05 energy =
> -1982.8383813757
>
> ----------------------------------- OT
> ---------------------------------------
>
> Allowing for rotations: F
> Optimizing orbital energies: F
> Minimizer : CG : conjugate gradient
> Preconditioner : FULL_ALL : diagonalization, state selective
> Precond_solver : DEFAULT
> Line search : 2PNT : 2 energies, one gradient
> stepsize : 0.05000000
> energy_gap : 0.00100000
>
> eps_taylor : 0.10000E-15
> max_taylor : 4
>
> mixed_precision : F
>
> ----------------------------------- OT
> ---------------------------------------
>
> Step Update method Time Convergence Total energy
> Change
>
> ------------------------------------------------------------------------------
>
> Trace(PS): 1174.9999628452
> Electronic density on regular grids: -1174.9999628438
> 0.0000371562
> Core density on regular grids: 1174.9999998887
> -0.0000001113
> Total charge density on r-space grids: 0.0000370449
> Total charge density g-space grids: 0.0000370449
>
> 1 OT CG 0.50E-01 24.7 0.00073898 -1982.8383578477
> 1.74E-06
>
> Trace(PS): 1174.6089204778
> Electronic density on regular grids: -1174.6089204763
> 0.3910795237
> Core density on regular grids: 1174.9999998887
> -0.0000001113
> Total charge density on r-space grids: 0.3910794124
> Total charge density g-space grids: 0.3910794124
>
> 2 OT LS 0.16E-01 6.8 -1982.7669389193
>
> Trace(PS): 1174.8781005916
> Electronic density on regular grids: -1174.8781005901
> 0.1218994099
> Core density on regular grids: 1174.9999998887
> -0.0000001113
> Total charge density on r-space grids: 0.1218992986
> Total charge density g-space grids: 0.1218992986
>
> 3 OT CG 0.16E-01 12.3 0.00075231 -1982.7595972134
> 7.88E-02
>
>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20130821/12c89017/attachment.htm>
More information about the CP2K-user
mailing list