Dear all,
In my MD simulation system, I have 2 sets of moleculse that need to added a external force, how to deal with that, can I write such a perl script as below?

#!perl

use strict;
use Math::Trig;
use Getopt::Long;
use MaterialsScript qw(:all);

my \\\$doc = \\\$Documents{"MFI5.xsd"};

my \\\$totalTime = 400;
my \\\$interval = 4;
my \\\$period = 800;
my \\\$forceAmplitude = 69.92; # kcal/mol/A

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

Modules->Forcite->ChangeSettings([Ensemble3D => "NVT",
Temperature => 348, 
TimeStep=> 2, 
EnergyDeviation=> 500000,
 NumberOfSteps=>2000,
 TrajectoryFrequency=>500,
 Thermostat=>"Berendsen",
 CurrentForcefield=>"Dreiding",
 Quality=>"Coarse",
 ChargeAssignment=>"Use current",
 "3DPeriodicElectrostaticSummationMethod"=>"Atom based",
 ]);

my \\\$xtd = \\\$dynamics->Run(\\\$doc, Settings(NumberOfSteps => 1))->Trajectory;

Modules->Forcite->ChangeSettings(Settings(
    TrajectoryRestart => "Yes", 
    AppendTrajectory => "Yes"));

for(my \\\$time = 0; \\\$time < \\\$totalTime; \\\$time += \\\$interval)
{
    my \\\$force = \\\$forceAmplitude*sin(\\\$time/\\\$period*2*pi);
    

    my \\\$externalForceStrength = \\\$force ;
    
    my \\\$results = \\\$dynamics->Run(\\\$xtd, Settings(
        ExternalForceSet => "Top",  
        ExternalForceStrength => \\\$externalForceStrength, 
        ExternalForceX=>0,
        ExternalForceY=>-1,
        ExternalForceZ=>0,
        ExternalForceSet => "Bottom",  
        ExternalForceStrength => \\\$externalForceStrength, 
        ExternalForceX=>0,
        ExternalForceY=>1,
        ExternalForceZ=>0,

    ));
}

Thank.
Best regards,
Yours
CHENG Xu