What does the compressibility parameter do?

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GROMACS version: 2023.2
GROMACS modification: Yes/No
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Hi everyone,

I was wondering what is the influence that the compressibility parameter has on the barostat?
I am trying to equilibrate a non-water solvent box and the density comes crashing down in NPT, and that’s the only problem I have been able to identify so far (I was using the compressibility value for water)

Cheers
Joan

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On technical aspects-When i used compressiblity of water for some of the solvents, i found formation of nanobubles in the simulation as well as the unstable simulations.

on the contest of barostat wrong compressibility gives inaccurate density and eventually leads to unphysical simulations.

Regarding the non-water solvent (DMSO), i increase the equilibration time and calcuated average density was found to be 1079.75 (kg/m^3) the reported density of DMSO is 1100 (kg/m^3). However i have seen big difference in density for the solvents which has compressibility various in the order of 1000.

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Hi,

I think a similar issue has been posted here: Acetone Solvent Box Simulation