net charge warning

[Monica_Gao]

Dear Dr. David.

   I am sure the total charge of my MOF and adsorbate are zero, but there are still show having net charge warning in my Output files, can you help me with this problem?

   Another problem is that, My adsorption condition is at ambient temperature and atmosphere pressure. and the fugacity of my adsorbate is lower than the vapor pressure, which means the partial pressure of this adsorbate is lower than its vapor pressure at atmosphere, so can you tell me why the excess adsorption is negative.

   The last but not least, can you tell me is there any good way to accelerate calculation.

   I am very grateful if you answer my questions, thank you very much.

[dubbelda]

Recheck how you use the charges, whether you use them from the 'pseudo_atoms.def' files or whether you use them directly from the CIF-file.

When you have negative excess adsorption, you crossed the vapor pressure according to the Peng-Robinson equation of state are inputted from the critical constants in the molecule file.
So either that is inaccurate, or your force field parameters of the molecule does not reproduces that vapor pressure.