Hello,everyone

I am a new user of MS script and hope some experienced users can give me some advice.

I want to simulate the melting point of LiCl-KCl by cooling it from 723K to another lower temperature with a Perl script to observe the MSD (or density or some other property of it).

Here is my code:

==========================================

#!perl

{

use strict;

use Getopt::Long;

use MaterialsScript qw(:all);

my \\\$deltaT=20;

my \\\$Tempchangetimes=1;

my \\\$NumberOfSteps = 20000;

my \\\$doc = \\\$Documents{"H2O.xsd"};

my \\\$newdoc = Documents->New("Hello.xtd");

sub Run {

   my (\\\$doc) = @_;

}

my \\\$forcite = Modules->Forcite;

my \\\$dynamics = Modules->Forcite->Dynamics;

for (my \\\$i = 0) {

    \\\$forcite->ChangeSettings([

                    Ensemble3D =>"NVT",

                    CurrentForcefield => "COMPASS",                     # force field to be used in the simulations

                    Temperature=>723-\\\$deltaT*\\\$i,

                    Thermostat => "Nose",                                        # type of thermostat to use

      BerendsenThermostatDecayConstant => 0.1,           # thermostat parameter

      "3DPeriodicvdWSummationMethod" => "Atom based", # van der Waals method to use

      TimeStep => 1,                                                  # time step (in fs)

      NumberOfSteps => \\\$NumberOfSteps,

      ]);    

    my \\\$results = Modules->Forcite->Dynamics->Run(\\\$doc, \\\$forcite);

    my \\\$docdelete = \\\$Documents{"H2O.xtd"};

    \\\$newdoc->Trajectory->AppendFramesFrom(\\\$doc,Frames(Start=>1,End=>\\\$NumberOfSteps));

    \\\$docdelete->Delete;

}

for (my \\\$i = 1; \\\$i <= \\\$Tempchangetimes; ++\\\$i) {

    \\\$forcite->ChangeSettings([

                    Ensemble3D =>"NVT",

                    CurrentForcefield => "COMPASS",                     # force field to be used in the simulations

                    Temperature=>723-\\\$deltaT*\\\$i,

                    Thermostat => "Nose",                                        # type of thermostat to use

      BerendsenThermostatDecayConstant => 0.1,           # thermostat parameter

      "3DPeriodicvdWSummationMethod" => "Atom based", # van der Waals method to use

      TimeStep => 1,                                                  # time step (in fs)

      NumberOfSteps => \\\$NumberOfSteps,

      InitialVelocities => "Current"

      ]);    

    my \\\$results = Modules->Forcite->Dynamics->Run(\\\$doc, \\\$forcite);

    my \\\$docdelete = \\\$Documents{"H2O.xtd"};

    \\\$newdoc->Trajectory->AppendFramesFrom(\\\$doc,Frames(Start=>1,End=>\\\$NumberOfSteps));

    \\\$docdelete->Delete;

}

}

But when i analyze the MSD of the xtd file, it shows "Mean square displacement analysis failed. The times associated with the first two selected fames are both zero"

I guess it because all the trajectories are counted from zero not continued.

Are there any method can fixed this problem??

Thanks in advance,

Regards,

Bill