GCMC gas adsorption

Hello users,

I am trying to reproduce the adsorption isotherm reported here(https://pubs.acs.org/doi/pdf/10.1021/ja076595g) using GCMC simulations.

Simulations were carried out at 300 K and 30 atm for CO2 uptake. Using the experimental data and other reported simulation data, number of CO2 at 30 atm are in order of few hundred.
However, I am able to see only a few CO2 (less than 10) adsorbed by MOF. I have changed parameters such as max. translation move, average number of MC moves, number of steps to invoke MC but did not see any significant change.

Later, I have printed the number of attempts and their corresponding success moves. As many as insertion successes, there were deletion successes which result in the fewer uptake of CO2.
Before posting here, I went through mailing lists, examples and simpler test but still could not able to figure why only a few CO2 were adsorbed.

I am using LAMMPS-17Jan 18 version and files are been attached for reproducing this behavior.
I would really appreciate if someone can help me. Thanks in advance.

Thanks,
Karteek

co2.dat (372 Bytes)

in.lammps (1.66 KB)

mof_m_l6_l6_l6.dat (33.2 KB)