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 |