[CP2K-user] Transition form PBE0 to PBE with CUTOFF_RADIUS 6.0: How to choose the vdW POTENTIAL R_CUTOFF?
Vyacheslav Bryantsev
vyachesla... at gmail.com
Tue Apr 14 14:57:16 UTC 2020
Dear CP2K Community,
I am using truncated Coulomb operator with long range correction to go
smoothly from PBE0 to PBE with CUTOFF_RADIUS 6.0 (the &XC block is defined
below).
My question is how one should define the vdW_POTENTIAL R_CUTOFF parameter
in this case. Here I am using PBED3 for PBE0 with R_CUTOFF 40.0.
I assume that beyond CUTOFF_RADIUS 6.0 it would still be applied based on
PBE0, not PBE. Is there a way to make vdW_POTENTIAL consistent for
different distances, or perhaps, this is not a big deal? Please advise.
Another ulrelated question for setting up PBE0 calculations.
In several tutorials online, EPS_SCHWARZ 1.0E-6, was used.
However, in this forum, EPS_SCHWARZ 1.0E-10 or even 1.0E-12 was
recommended. Since I would like to generate a trajectory of several tens on
ps, having low threshold on this parameter is unpractical. Would
EPS_SCHWARZ 1.0E-6 be still a good compromise?
Thank you,
Slava
&XC
&XC_FUNCTIONAL
&PBE
SCALE_X 0.75
SCALE_C 1.0
&END PBE
&PBE_HOLE_T_C_LR
CUTOFF_RADIUS 6.0
SCALE_X 0.25
&END PBE_HOLE_T_C_LR
&END XC_FUNCTIONAL
&vdW_POTENTIAL
DISPERSION_FUNCTIONAL PAIR_POTENTIAL
&PAIR_POTENTIAL
R_CUTOFF 40.0
TYPE DFTD3
PARAMETER_FILE_NAME dftd3.dat
REFERENCE_FUNCTIONAL PBE0
&END PAIR_POTENTIAL
&END vdW_POTENTIAL
&HF
&SCREENING
EPS_SCHWARZ 1.0E-6
SCREEN_ON_INITIAL_P FALSE
&END SCREENING
&INTERACTION_POTENTIAL
POTENTIAL_TYPE TRUNCATED
CUTOFF_RADIUS 6.0
T_C_G_DATA ./t_c_g.dat
&END INTERACTION_POTENTIAL
&MEMORY
MAX_MEMORY 3000
EPS_STORAGE_SCALING 0.1
&END MEMORY
FRACTION 0.25
&END HF
&END XC
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