Isothermal Compressibility of Liquid Water at pressure = 1 atm

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1

GROMACS version: 2020.2
GROMACS modification: No
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Hi,

I have a quick question about determining the Isothermal Compressibility of Liquid Water at pressure = 1 atm on Gromacs simulation.
I found a paper below about the Isothermal Compressibility of Liquid Water at 1 atm.

https://pubs.acs.org/doi/10.1021/je60044a003

On page 121, there is a table (table II) showing the Isothermal Compressibility of Water at different temperatures. For example, for the temperature = 5 ℃, the suggested compressibility value is 4.9e-5 bar (~atm). Would it be possible to just use this value for the compresibility value in .mdp file when I do the pressure coupling if I want to do a simulation (water box with a protein) at 1 atm and 5 ℃ for example?

Thank you for your help.

2

Hi,
you can change the value of isothermal compressibility, but it is good to check what happen to the water model when you do that. For example you can check by running a water box at the new condition and check that the property you get are correct (e.i density). Note the standard biomolecular force field are effective poentials that are parameterized for room temperature and 1 atm, thus one can not assume that they work under other condition.
Best regards
Alessandra

3

Hi Alessandra,

That sounds very reasonable. I’ll first try checking that before I run my simulation. Thank you so much for your help!

Best Regard,
Karin