Antwort: [CP2K:3347] BOMD - Total energy increasing

[hut... at pci.uzh.ch]

Hi

Looking at your energy plot I would guess that the problem is 
related to the numerics of the BLYP functional. You can either
increase the energy cutoff from 280 Ry to a considerable higher
value or use a smoothing procedure of the density.
XC_SMOOTH_RHO NN50
would be my choice.

regards

Juerg 

--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich               E-mail:  hut... at pci.uzh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com schrieb: -----
An: cp... at googlegroups.com
Von: Sandeep Kumar Reddy 
Gesendet von: cp... at googlegroups.com
Datum: 07/01/2011 10:42AM
Betreff: [CP2K:3347] BOMD - Total energy increasing

Dear all,
              I am doing an BOMD run of carboxylic acid in water. After 6ps, i plotted conserved quantity as a function of step no.  which shows total energy is increasing.  Can anybody help
why it is increasing ?
 
Input file :

&FORCE_EVAL
  METHOD Quickstep
  &DFT
    BASIS_SET_FILE_NAME BASIS_MOLOPT
    POTENTIAL_FILE_NAME POTENTIAL
    CHARGE = 0  
    &MGRID
      CUTOFF 280
      NGRIDS 5 
       REL_CUTOFF 40
    &END MGRID
     &QS
       METHOD GPW
       EPS_DEFAULT 1.0E-10
     &END QS
     &SCF
       SCF_GUESS ATOMIC 
       EPS_SCF 1.0E-6
       MAX_SCF 150
 #       MIXING 0.3
       &OUTER_SCF
          EPS_SCF 1.0E-6
          MAX_SCF 50
       &END
    &OT
          MINIMIZER CG
          PRECONDITIONER FULL_ALL
          ENERGY_GAP 0.001
           STEPSIZE 0.05
       &END
 
    &END SCF
    &XC
     &XC_FUNCTIONAL BLYP 
      &END XC_FUNCTIONAL
      &vdW_POTENTIAL
         DISPERSION_FUNCTIONAL PAIR_POTENTIAL
          &PAIR_POTENTIAL
            TYPE DFTD2
            REFERENCE_FUNCTIONAL BLYP 
         &END PAIR_POTENTIAL
      &END vdW_POTENTIAL
 
   &END XC
  &END DFT

  &SUBSYS
     &CELL 
      ABC 12.16174 12.16174 12.16174
    &END CELL

    &COORD
     @INCLUDE coor.xyz 
    &END COORD

     &KIND O
      BASIS_SET TZV2P-MOLOPT-GTH-q6 
      POTENTIAL GTH-BLYP-q6
     &END KIND
    
    &KIND C
      BASIS_SET TZV2P-MOLOPT-GTH-q4 
      POTENTIAL GTH-BLYP-q4
    &END KIND

    &KIND H
      BASIS_SET TZV2P-MOLOPT-GTH-q1 
      POTENTIAL GTH-BLYP-q1
       MASS 1.00794
    &END KIND

  &END SUBSYS
&END FORCE_EVAL

&GLOBAL
  PROJECT OUT-URACIL-MD
  RUN_TYPE MD
  PRINT_LEVEL MEDIUM
&END GLOBAL

&MOTION
  &MD
     ENSEMBLE NVT
    STEPS 100000
    TIMESTEP 0.5
    &THERMOSTAT
      &NOSE
        LENGTH 3
        YOSHIDA 3
        TIMECON 100.0
        MTS 2
      &END NOSE
    &END THERMOSTAT
   TEMPERATURE 298.15
  &END MD
&END MOTION


----


Thanks & Regards,
Sandeep kumar Reddy
Ph. D. student








  
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[Anhang 'Untitled.png' entfernt von Jürg Hutter/at/UZH]