[CP2K:662] MD simulation doesn't run very long

[Teodoro Laino]

Ciao Andrew,

> lammps but cp2k ran into some connectivity issues (cp2k doesn't seem
> to find water molecules automatically across cell boundaries).  I
this is not the case.. cp2k uses PBC also to identify the connectivity..
The point could be that water is a little bit tricky.. if the  
geometry is a little bit distorted with hydrogen bonds is
anyway difficult to identify a proper water molecule as an  
independent unity..
That's why is always better in my opinion to use an external topology  
file as you did after..

> fixed this, by making certain the water molecules were all in the
> image reference and defining the connectivity manually.  This didn't
> fix that specific problem though: the symptom is that the simulation
> runs for ~20-30 time steps and then the temperature increases
> dramatically and we get some atoms crash:

I was running your input file for several time steps (see the  
attached output file) and I don't get
any error..
I suppose gfortran is miscompiling cp2k (and I would not be  
surprised.. as far as I know only very recent version of gfortran
can compile cp2k)..

I would suggest you to use g95 (if you want to go for a free  
compiler) or intel.

I'm sorry but as you may have already read on this group cp2k is  
quite demanding in terms of fortran compilers..
Hope this helps!
Teo

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>
>
>
> ********************************************************************** 
> *********
>  ENSEMBLE TYPE
> =                                              nvt
>  STEP NUMBER
> =                                               26
>  TIME [FS]                    =
> 26.000000
>  CONSERVED QNTY               =
> -0.299834451059E+01
>
>                                          INSTANTANEOUS        AVERAGES
>  CPU [S]                      =
> 0.22                 0.39
>  {E-E0}/{k_b*N_at}            =          0.396202120408E+02
> 0.335570376311E+01
>  POTENTIAL ENERGY[hartree]    =         -0.549743589253E+01
> -0.462863744377E+01
>  KINETIC ENERGY[hartree]      =          0.249463138359E+01
> 0.153631845774E+01
>  TEMPERATURE[K]               =
> 656.451              404.275
>
> ********************************************************************** 
> *********
>
>  WARNING| Particles:     609    265 at distance [au]:     0.49549362
> less than:      0.95400000; increase EMAX_SPLINE.
>
> The temperature was supposed to be 300 K, but as you can see it blows
> up the last few time steps.
>
> Here is a link to the files:
> http://shadow.eas.gatech.edu/~astack/water.tar.gz
>
> Here is my input file, the commented out sections are different things
> we tried to see if that made a difference.  The biggest thing that
> seemed to affect the number of time steps was the options affecting
> the spline.
>
> &FORCE_EVAL
>   METHOD FIST
>   &MM
>     &FORCEFIELD
> !       &SPLINE
> !               EMAX_SPLINE 1000.0
> !               R0_NB [angstrom] 0.1
> !       &END SPLINE
>       &BEND
>          ATOMS H O H
>          KIND HARMONIC
>          K [kcalmol*rad^-2] 120
>          THETA0 [deg] 109.47
>        &END BEND
>        &BOND
>          ATOMS O H
>          KIND HARMONIC
>          K [kcalmol*angstrom^-2] 500
>          R0 [angstrom] 1.00
>        &END BOND
>       &NONBONDED
>         &LENNARD-JONES
>            ATOMS O O
>            EPSILON [kcalmol] 0.1848
> !           SIGMA [angstrom] 3.5532
>            SIGMA [angstrom] 3.1655
>            RCUT [angstrom] 10.0
>          &END LENNARD-JONES
>          &LENNARD-JONES
>            ATOMS O H
>            EPSILON [kcalmol] 0.0430
> !           SIGMA [angstrom] 1.7883
>            SIGMA [angstrom] 1.5932
>            RCUT [angstrom] 10.0
>          &END LENNARD-JONES
>          &LENNARD-JONES
>            ATOMS H H
>            EPSILON [kcalmol] 0.0100
> !           SIGMA [angstrom] 0.900
>            SIGMA [angstrom] 0.8018
>            RCUT [angstrom] 10.0
>          &END LENNARD-JONES
>       &END NONBONDED
>     &END FORCEFIELD
>     &POISSON
>       &EWALD
>         EWALD_TYPE ewald
>         ALPHA 0.5
>         GMAX 15
>       &END EWALD
>     &END POISSON
>   &END MM
>   &SUBSYS
>     &CELL
>       ABC 20 20 20
>       UNIT ANGSTROM
>       PERIODIC XYZ
>     &END CELL
>     &TOPOLOGY
>         CONN_FILE_NAME water.psf
>         CONNECTIVITY UPSF
>         COORD_FILE_NAME water.pdb
>         COORDINATE PDB
>     &END TOPOLOGY
>     &PRINT
>       &TOPOLOGY_INFO HIGH
>         FILENAME topology.inf
>         PDB_INFO
>         COMMON_ITERATION_LEVELS 1
>         UTIL_INFO
>         GENERATE_INFO
>       &END TOPOLOGY_INFO
>     &END PRINT
>   &END SUBSYS
> !  &RESCALE_FORCES
> !    MAX_FORCE 0.001
> !  &END
> !  &PRINT
> !       &FORCES
> !         FILENAME water.force
> !        &END FORCES
> !  &END PRINT
> &END FORCE_EVAL
> &GLOBAL
>   PROJECT water
>   RUN_TYPE MD
> !  PRINT_LEVEL HIGH
> &END GLOBAL
> &MOTION
>   &MD
>     ENSEMBLE NVT
>     STEPS 300
>     TIMESTEP 1
>     TEMPERATURE 300
> !    TEMP_TOL 1.0
>    &THERMOSTAT
>     &NOSE
>       LENGTH 1
>       YOSHIDA 3
>       MTS 2
>       TIMECON 500
>     &END NOSE
>    &END THERMOSTAT
>    &PRINT
>     &ENERGY HIGH
>      EACH 1
>     &END ENERGY
>    &END PRINT
>   &END MD
> &END MOTION
>
>
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