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