convergence issues with rCAM-B3LYP
Rad
rad.... at arl.army.mil
Thu Feb 21 15:12:08 CET 2008
Dear All,
I managed to compile cp2k (Last CVS entry qs_scf_post.F/
1.149/Wed Feb 13 23:07:05 2008) with libint (thaks to Teo's
suggestions) and tested the sample input that uses rCAM-B3LYP. This
input file was set up to do a single point energy calculation. I
adopted the same input file for my system with just 56 atoms and tried
a simple geometry optimization. The wave function is not converging at
all (at most I got two convergences of the outer loop). Here is the
input section I used:
&FORCE_EVAL
METHOD Quickstep
&DFT
BASIS_SET_FILE_NAME EMSL_BASIS_SETS
POTENTIAL_FILE_NAME POTENTIAL
&MGRID
CUTOFF 1600
NGRIDS 5
REL_CUTOFF 50
&END MGRID
&QS
METHOD GAPW
MAP_CONSISTENT
EXTRAPOLATION PS
EXTRAPOLATION_ORDER 2
&END QS
&SCF
&OT on
MINIMIZER DIIS
PRECONDITIONER FULL_SINGLE_INVERSE
STEPSIZE 0.05
&END OT
&OUTER_SCF
EPS_SCF 1.0E-6
MAX_SCF 40
&END OUTER_SCF
EPS_SCF 1.0E-6
SCF_GUESS RESTART
MAX_SCF 500
&END SCF
&XC
&XC_FUNCTIONAL
&BECKE88
SCALE_X 0.95238
&END
&BECKE88_LR
OMEGA 0.33
SCALE_X -0.94979
&END
&LYP
SCALE_C 1.0
&END
&XALPHA
SCALE_X -0.13590
&END
&END XC_FUNCTIONAL
&HF
&SCREENING
EPS_SCHWARZ 1.0E-10
EPS_BOX 1.0E-10
&END
&MEMORY
MAX_MEMORY 100
&END
&INTERACTION_POTENTIAL
POTENTIAL_TYPE MIX_CL
OMEGA 0.33
SCALE_LONGRANGE 0.94979
SCALE_COULOMB 0.18352
&END
&END
&END XC
&END DFT
Could you please take a look at it and offer me suggestions to tweak
the parametrs for wavefunction convegence.
I also tried CG with different step sizes in the OT section and also a
run without OT section but still no convergence at all. I will
appreciate any suggestions/pointers you may offer in this regard.
Thanks
Rad
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