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Mixture GCMC: CO2 and Methane Adsorption in MOF MATVAF

Introduction

  • Bae and co-authors published a paper of simulating CO2/Methane separation using a mix-ligand MOF
  • They conducted mixture GCMC simulation using the MuSiC code

✍ simulation.input

NumberOfInitializationCycles 100000
NumberOfEquilibrationCycles  0
NumberOfProductionCycles     100000

UseChargesFromCIFFile yes

UseMaxStep  yes
MaxStepPerCycle 1

RestartFile no
RandomSeed  0

NumberOfTrialPositions 10
NumberOfTrialOrientations 10

NumberOfBlocks 1
AdsorbateAllocateSpace 10240
NumberOfSimulations 1
SingleSimulation yes

InputFileType cif
FrameworkName MATVAF_clean-Bae-PartialCharge-fixed-Original-N2-Charge
UnitCells 0 3 3 2

ChargeMethod Ewald
Temperature  296
Pressure     500000

OverlapCriteria 1e5
CutOffVDW 12.8
CutOffCoulomb 12.0
EwaldPrecision 1e-6

Component 0 MoleculeName              CO2
            IdealGasRosenbluthWeight  1.0
            FugacityCoefficient       0.9730021872
            MolFraction               0.5
            TranslationProbability    1.0
            RotationProbability       1.0
            ReinsertionProbability    1.0
            IdentityChangeProbability 1.0
            SwapProbability           1.0
            CreateNumberOfMolecules   0

Component 1 MoleculeName              methane
            IdealGasRosenbluthWeight  1.0
            FugacityCoefficient       0.9894689168
            MolFraction               0.5
            TranslationProbability    1.0
            ReinsertionProbability    1.0
            IdentityChangeProbability 1.0
            SwapProbability           1.0
            CreateNumberOfMolecules   0

📝 Special Notes!

  • gRASPA supports fugacity coefficient calculations using Peng-Robinson Equation of State
    • use keyword FugacityCoefficient PR-EOS for each component to call Peng-Robinson coefficient calculation
  • Use IdentityChangeProbability 1.0 to improve the sampling
    • It is fine not to use Identity swap, since GCMC swap move is sufficient.
  • The value reported by Bae et al. are excess loadings, while currently gRASPA reports absolute loadings
    • 💡 One can try feeding the gRASPA restart file to RASPA-2 and run zero-cycle
      • This will calculate the excess-loading for the snapshot in the gRASPA restart file.
      • 📝 Look at the GCMC basics for more