[CP2K:10253] MD melting problem

[Josip Lovrić]

Normaly, phase transitions are hard to reproduce. You are not first one to
be frustrated. Secondly 100 ps is way to short, you need to go at least to
10s of ns and maybe if you are lucky you will see some melting. Also, do
you have slab or bulk?

Josip
Greetings from Gothenburg

2018-05-03 2:37 GMT+02:00 <4985... at qq.com>:

> Hello, everyone, I recently want simulated the melting structure of molten
> salts. The simulation begin with the crystal structure and intend to be
> melt at 3000 K in NPT ensemble， but the result is frustrating. After 100 ps
> runs, the ions still in crystal structure. The parameters in the force
> field is in published paper and widely used, so I wonder maybe I write
> something of the input wrong. The input file is listed below, pls help out
> the dilemma, thanks very much.
>
>
> &GLOBAL                         ! Section with general information
> regarding which kind of simulation to perform an parameters for the whole
> PROGRAM
>   PROJECT C6                    ! Name of the project. This word will
> appear as part of a name of all ouput files (except main ouput file,
> specified with -o option)
>   RUN_TYPE MD           ! Molecular Dynamics
>   PRINT_LEVEL low
> &END GLOBAL
>
>
> &FORCE_EVAL ! This section defines method for calculating energy and
> forces
>   METHOD FIST ! Using Molecular Mechanics
>   STRESS_TENSOR NUMERICAL
>   &MM
>     &FORCEFIELD ! This section specifies forcefield parameters
>       ..........
>     &END FORCEFIELD
>     &POISSON ! This section specifies parameters for the Poisson solver
>       &EWALD ! This section specifies parameters for the EWALD summation
> method (for the electrostatics)
>         EWALD_TYPE none ! Standard real-space coulomb potential is
> computed together with the non-bonded contributions.
>       &END EWALD
>     &END POISSON
> &NEIGHBOR_LISTS
>   GEO_CHECK TRUE
>   NEIGHBOR_LISTS_FROM_SCRATCH TRUE
>   VERLET_SKIN 1
>     &END NEIGHBOR_LISTS
>   &END MM
>   &SUBSYS ! This section defines the system
>     &CELL ! Unit cell set up
>       ABC 22.56 22.56 22.56 ! Lengths of the cell vectors A, B, and C
>       ALPHA_BETA_GAMMA 90.0 90.0 90.0
>       PERIODIC  XYZ
>     &END CELL
>     &TOPOLOGY
>      COORD_FILE_NAME  NaCl.xyz
>      COORDINATE xyz ! The type of the file  is XYZ
>     &END TOPOLOGY
>   &END SUBSYS
> &END FORCE_EVAL
>
> &MOTION ! This section defines a set of tool connected with the motion of
> the nuclei.
>  &PRINT
>  &TRAJECTORY
>     LOG_PRINT_KEY T
>     FORMAT XMOL
>     &EACH
>      MD 10000
>     &END EACH
>     ADD_LAST NUMERIC
>  &END TRAJECTORY
>  &END PRINT
>  &MD
>     ENSEMBLE NPT_I
>     TEMPERATURE 3000
> &BAROSTAT
>   PRESSURE 0
>   TEMPERATURE 3000
> &END BAROSTAT
> &THERMOSTAT
>         TYPE NOSE
>          REGION GLOBAL
>          &NOSE
>            TIMECON 100
>            LENGTH 3
>            MTS 2
>          &END NOSE
>      &END THERMOSTAT
> TIMESTEP 1.0
> STEPS 100000
>  &END MD
>
>   &PRINT
>     &RESTART
>       LOG_PRINT_KEY T
>       &EACH
>         MD 10000
>       &END EACH
>       ADD_LAST NUMERIC
>     &END RESTART
>   &END PRINT
> &END MOTION
>  &END
> &END MOTION
>
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