Heat of adsorption of CO2 in MOF

GROMACS version:2019
GROMACS modification: Yes/No
Here post your question
Hello everyone,

I am currently studying the capture of CO2 with a metal-organic framework (MOF). I would like to calculate the heat of adsorption of CO2 but I am not sure about the methodology. So far, I have inserted one single CO2 molecule in the unit cell and performed preliminary MD calculations (geometry optimization and NPT equilibration) with gromacs 2019.
Now, I am wondering which ensemble I should use (NVT or NPT) for the calculation of the heat of adsorption, and for which key parameters I should pay attention in the .mdp file ? For instance, I assume that I should separate the energy groups (the residues instead of ‘system’). What should be the minimum electrostatic and vdW cutoff for such kind of calculation? Etc.

Finally, I’d like to know if gromacs has an internal program that can quickly calculate the heat of adsorption. If not, how should I proceed? Is the heat of adsorption a formula as simple as:
H_CO2-in-MOF - H_CO2 - H_MOF ?
Does anyone have any clue or experience related to that?

Your help is highly appreciated.