SMF - Just Installed!

Main Menu

Problem with pressure calculations during adsorption

Started by Temoor, April 19, 2023, 10:07:45 PM

Previous topic - Next topic


When I simulate the adsorption of my fluid on the mineral surface, I set up my external pressure to 1MPa. Now, I enabled the keyword of CalculateMolecularPressure. During the simulation, I get a pressure of 12MPa instead of 1MPa. I am unsure why it is not showing 1MPa partial pressure of my fluid.

I have tried the examples provided in the RASPA manual, and they give the same overestimated pressures during adsorption. What are the possible reasons for it? Am I setting the system wrong or the pressures are fine?


David Dubbeldam

Pressure is not well-defined if you use a fixed framework. Even for a flexible framework, keep in mind that for solids pressures are in the orders of Gpa for a small structural difference and hence pressure for solids fluctuate a lot more than liquids, which fluctuate more than gases.