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Parameter file *.par

Following table lists all parameters and options to be specified in the input file *.par. An example for a complete *.par file is given below for a MC simulation of pure ethylene oxide in the NpT ensemble, where the chemical potential of ethylene oxide is calculated by gradual insertion.

Parameter

Option

Explanation

Recommended values

Units

SI

 

reduced

Physical properties in the *.par file are given in SI units

Physical properties in the *.par file are given in reduced units with respect to the reference values of length, energy and mass

SI

LengthUnit

EnergyUnit

MassUnit

 

Reference length ϭR in Ã?

Reference length ϵR/kb in K

Reference

3.0

100.0

100.0

Simulation

MD

MC

Molecular dynamics simulation

Monte Carlo simulation

 

Integrator

 

TimeStep

Gear

Leapfrog

Gear predictor-corrector integrator (MD only)

Leapfrog integrator (MD only)

Time step of one MD step (MD only)

Gear

 

~1 fs

Acceptance

 

Acceptance rate for the MC moves (MC only)

0.5

Ensemble

NVT

NVE

NpT

GE

Canonical ensemble

Micro-canonical ensemble

Isobaric-isothermal ensemble

Grand equilibrium method (pseudo-μVT)

 

MCORSteps

NVTSteps

 

NPTSteps

 

RunSteps

 

MC relaxation loops for pre-equilibration

Number of equilibration time steps (MD) or loops (MC) in the NVT ensemble

Number of equilibration time steps (MD) or loops (MC) in the NpT ensemble

Number of production time steps (MD) or loops (MC)

100

20000

 

50000

 

300000

ResultFreq

ErrorFreq

 

VisualFreq

 

Size of block averages in time steps or loops

Frequency of writing the file *.res file in time steps or loops

Frequency of saving configurations in the *.vim file for visualization in time steps or loops

100

5000

 

5000

CutoffMode

COM

Site

Center of mass cut-off

Site-site cut-off

COM

NEnsemble

 

Number of ensembles in the simulation

1

CorrfunMode

yes

no

Calculation of autocorrelation functions enabled

Calculation of autocorrelation functions disabled

 

Temperature

Pressure

Density

PistonMass

 

NParticles

 

Specified temperature

Specified pressure

Specified density

Piston mass for simulations at constant pressure

Total number of particles

 

 

 

 

864-4000

NComponents

 

Number of components in the simulation

 

Corrlength

SpanCorrFun

 

ViewCorrFun

 

ResultFreqCF

 

Length of the autocorrelation in time steps

Time steps separating subsequent autocorrelation functions

Output of the full autocorrelation functions into the *.rtr file

Output of transport properties into the *.res file

 

PotModel

MolarFract

ChemPotMethod

 

 

 

 

 

 

NTest

 

WeightFactors

 

 

none

 

Widom

 

 

GradIns

 

 

 

Guess

 

 

OptSet

Model file *.pm of a component

Mole fraction of a component

No calculation of the chemical potential for this component

Calculation of the chemical potential for this component using Widom's test molecule method

Calculation of the chemical potential for this component using gradual insertion

Number of test molecules for Widom's test molecule method

For gradual insertion: use user defined initial values for the weight factors - optimization of the factors during the simulation

For gradual insertion: use user defined values for the weight factors without change during simulation

 

 

none

 

 

 

 

 

 

2000

 

Guess

Cutoff

CutoffLJ

 

CutoffDD

 

CutoffDQ

 

CutoffQQ

 

Cut-off radius for center of mass cut-off

Cut-off radius for LJ-interactions (site-site cut-off)

Cut-off radius for dipole-dipole interactions (site-site cut-off)

Cut-off radius for dipole-quadrupole interactions (site-site cut-off)

Cut-off radius for quadrupole-quadrupole interactions (site-site cut-off)

 

Epsilon

 

Dielectric constant

1.0E+10

 

Download example Parameter file (390.par)