[CP2K-user] [CP2K:13074] NPT simulation of 64 water molecules

Travis polla... at gmail.com
Tue Apr 7 18:58:53 UTC 2020


Hi,

SCALE_C set to zero ignores the correlation part of the potential, hence 
the much smaller than expected density. Delete this line or set it to 1 
(default is 1).

-T

On Tuesday, April 7, 2020 at 2:42:41 PM UTC-4, Anna Varghese wrote:
>
> Dear Thomas, 
>
> Thank you, for the reply. I am not sure about SCALE, I saw it on one 
> website. Please find the attached density plot. Please let me know the 
> corrections.
>
> Thanks
> Anna.
>
> On Tue, Apr 7, 2020 at 9:53 PM Thomas Kühne <t... at gmail.com 
> <javascript:>> wrote:
>
>> Dear Anna, 
>>
>> looks mostly fine to me. However, is SCALE_C 0.0 intentionally and 
>> correct? 
>> If so, can you please provide a similar density plot than in the paper or 
>> at least 
>> quantify the drop in particle density?
>>
>> Cheers, 
>> Thomas
>>
>> Am 07.04.2020 um 12:56 schrieb ANNA VARGHESE <an... at gmail.com 
>> <javascript:>>:
>>
>>
>> Dear All,
>> I am trying to run NPT simulation of 64 water molecules following 
>> https://aip.scitation.org/doi/am-pdf/10.1063/1.4986284 .  I observe a 
>> drop in density at the end of density. Can anyone look at this input file 
>> and tell me where am I going wrong? 
>>
>> Thanks in advance,
>>
>>
>> &GLOBAL
>>   ! the project name is made part of most output files... useful to keep 
>> order
>>   PROJECT WATER
>>   ! various runtypes (energy, geo_opt, etc.) available.
>>   RUN_TYPE MD
>>   ! reduce the amount of IO
>>   IOLEVEL  LOW
>> &END GLOBAL
>>
>> &FORCE_EVAL
>>   ! the electronic structure part of CP2K is named Quickstep
>>   METHOD Quickstep
>> STRESS_TENSOR ANALYTICAL
>>   &DFT
>>     ! basis sets and pseudopotential files can be found in cp2k/data
>>     BASIS_SET_FILE_NAME GTH_BASIS_SETS
>>     POTENTIAL_FILE_NAME GTH_POTENTIALS            
>>
>>
>>     ! Charge and multiplicity
>>     CHARGE 0
>>     MULTIPLICITY 1
>>
>>     &MGRID
>>        ! PW cutoff ... depends on the element (basis) too small cutoffs 
>> lead to the eggbox effect.
>>        ! certain calculations (e.g. geometry optimization, vibrational 
>> frequencies,
>>        ! NPT and cell optimizations, need higher cutoffs)
>>        CUTOFF [Ry] 800 
>>     &END
>>
>>     &QS
>>        ! use the GPW method (i.e. pseudopotential based calculations with 
>> the Gaussian and Plane Waves scheme).
>>        METHOD GPW 
>>        ! default threshold for numerics ~ roughly numerical accuracy of 
>> the total energy per electron,
>>        ! sets reasonable values for all other thresholds.
>>        EPS_DEFAULT 1.0E-10 
>>        ! used for MD, the method used to generate the initial guess.
>>        EXTRAPOLATION ASPC 
>>     &END
>>
>>     &POISSON
>>        PERIODIC XYZ ! the default, gas phase systems should have 'NONE' 
>> and a wavelet solver
>>     &END
>>
>>     &PRINT
>>        ! at the end of the SCF procedure generate cube files of the 
>> density
>>        &E_DENSITY_CUBE OFF
>>        &END E_DENSITY_CUBE
>>        ! compute eigenvalues and homo-lumo gap each 10nd MD step
>>        &MO_CUBES
>>           NLUMO 4
>>           NHOMO 4
>>           WRITE_CUBE .FALSE.
>>           &EACH
>>             MD 10
>>           &END
>>        &END
>>     &END
>>
>>
>>  ! use the OT METHOD for robust and efficient SCF, suitable for all 
>> non-metallic systems.
>>     &SCF                              
>>       SCF_GUESS ATOMIC ! can be used to RESTART an interrupted calculation
>>       MAX_SCF 30
>>       EPS_SCF 1.0E-6 ! accuracy of the SCF procedure typically 1.0E-6 - 
>> 1.0E-7
>>       &OT
>>         ! an accurate preconditioner suitable also for larger systems
>>         PRECONDITIONER FULL_SINGLE_INVERSE
>>         ! the most robust choice (DIIS might sometimes be faster, but not 
>> as stable).
>>         MINIMIZER DIIS
>>       &END OT
>>       &OUTER_SCF ! repeat the inner SCF cycle 10 times
>>         MAX_SCF 10
>>         EPS_SCF 1.0E-6 ! must match the above
>>       &END
>>       ! do not store the wfn during MD
>>       &PRINT
>>         &RESTART OFF
>>         &END
>>       &END
>>     &END SCF
>>
>>     ! specify the exchange and correlation treatment
>>     &XC
>>       ! use a PBE functional 
>>       &XC_FUNCTIONAL 
>>          &PBE
>>           PARAMETRIZATION revPBE
>>           SCALE_C 0.0
>>          &END
>>       &END XC_FUNCTIONAL
>>       ! adding Grimme's D3 correction (by default without C9 terms) 
>>       &VDW_POTENTIAL
>>          POTENTIAL_TYPE PAIR_POTENTIAL 
>>          &PAIR_POTENTIAL
>>             PARAMETER_FILE_NAME dftd3.dat
>>             TYPE DFTD3
>>             REFERENCE_FUNCTIONAL PBE
>>             R_CUTOFF [angstrom] 16
>>          &END
>>       &END VDW_POTENTIAL
>>     &END XC
>>   &END DFT
>>  
>>   ! description of the system
>>   &SUBSYS
>>     &CELL 
>>       ! unit cells that are orthorhombic are more efficient with CP2K
>>       ABC [angstrom] 14.77 14.77 14.77
>>     &END CELL
>>
>>     ! atom coordinates can be in the &COORD section,
>>     ! or provided as an external file.
>>     &TOPOLOGY
>>       COORD_FILE_NAME water.xyz
>>       COORD_FILE_FORMAT XYZ
>>     &END
>>
>>     &KIND H
>>       BASIS_SET TZV2P-GTH
>>       POTENTIAL GTH-PBE-q1
>>     &END KIND
>>     &KIND O
>>       BASIS_SET TZV2P-GTH
>>       POTENTIAL GTH-PBE-q6
>>     &END KIND
>>
>>   &END SUBSYS
>> &END FORCE_EVAL
>>
>> ! how to propagate the system, selection via RUN_TYPE in the &GLOBAL 
>> section
>> &MOTION
>>  &GEO_OPT
>>    OPTIMIZER BFGS ! Good choice for 'small' systems (use LBFGS for large 
>> systems)
>>    MAX_ITER  100
>>    MAX_DR    [bohr] 0.003 ! adjust target as needed
>>    &BFGS
>>    &END
>>  &END
>>  &MD
>>    ENSEMBLE NPT_I  ! sampling the canonical ensemble, accurate properties 
>> might need NVE
>>    TEMPERATURE [K] 300
>>    TIMESTEP [fs] 0.5
>>    STEPS 10000
>>   &BAROSTAT
>>     PRESSURE 1.03                 # PRESSURE, unit[bar]
>>     TIMECON 300
>>   &END BAROSTAT
>>
>> &THERMOSTAT
>>     REGION MASSIVE
>>     &NOSE                    #Uses the Nose-Hoover thermostat
>>       TIMECON 11.12           #timeconstant of the thermostat chain, how 
>> often does thermostat adjust your system
>>     &END NOSE
>>   &END
>>
>>  &END
>>   &PRINT
>>    &TRAJECTORY
>>      &EACH
>>        MD 1
>>      &END EACH
>>    &END TRAJECTORY
>>    &VELOCITIES OFF
>>    &END VELOCITIES
>>    &FORCES OFF
>>    &END FORCES
>>    &RESTART_HISTORY
>>      &EACH
>>        MD 500
>>      &END EACH
>>    &END RESTART_HISTORY
>>    &RESTART
>>      BACKUP_COPIES 3
>>      &EACH
>>        MD 1
>>      &END EACH
>>    &END RESTART
>>   &END PRINT
>> &END
>>
>>
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>> .
>> <water.inp>
>>
>>
>>
>>
>> ==============================
>> Thomas D. Kühne
>> Dynamics of Condensed Matter
>> Chair of Theoretical Chemistry
>> University of Paderborn
>> Warburger Str. 100
>> D-33098 Paderborn
>> Germany
>> td... at mail.upb.de <javascript:>
>> +49/(0)5251/60-5726
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
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>> .
>>
>
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