The average loading of the MOF at a given pressure will be computed using grand-canonical Monte Carlo (GCMC) simulations with the RASPA code.

• The RASPA code needs several input parameters, some of which you will need to figure out

parameters = ParameterData(dict={
"GeneralSettings": {
"SimulationType"               : "MonteCarlo",
"NumberOfCycles"               : 2000,
"NumberOfInitializationCycles" : 2000,
"PrintEvery"                   : 2000,
"ChargeMethod"                 : "Ewald",
"CutOff"                       : 12.0,
"Forcefield"                   : "<string>",
"EwaldPrecision"               : 1e-6,
"Framework"                    : 0,
"UnitCells"                    : "<int> <int> <int>",
"HeliumVoidFraction"           : 0.0,
"ExternalTemperature"          : <float (Kelvin)>,
"ExternalPressure"             : <float (Pascal)>,
},
"Component": [{
"MoleculeName"                 : "methane"
"MoleculeDefinition"           : "TraPPE",
"TranslationProbability"       : 0.5,
"ReinsertionProbability"       : 0.5,
"SwapProbability"              : 1.0,
"CreateNumberOfMolecules"      :0,
}],
})

• Our simulations are performed under periodic boundary conditions. This means, we need to make our simulation cell large enough that a molecule will never interact with a two periodic copies of any of its neighbors. Given the cutoff radius of $$12$$ Angstroms, how often do you need to replicate the unit cell of the material?

Hint: The CIF files include information on the size of the unit cell.

• To make things more interesting, we are going to use different force fields. Ask your instructor to give you a force field identifier.

• You already performed a small GCMC calculation at 10 bar during the tutorial. Adapt the input file to your needs and run the calculation. Hint: Once running, the calculation should finish within 5 minutes.