Force field parameters for CO3, SO4 and HCO3

User discussions
1

Dear all,

I want to run a gromacs simulation of a system containing the following salts CaCO3, Na2SO4 and NaHCO3 dissolved in water. I know for instance CaCO3 is to be specified as Ca and CO3. I can get the force field parameters for Ca but how can I get that of CO3, SO4 and HCO3.

Many thanks and kind regards.

2

Dear @Nightwolf

What do you mean that you can get the parameters for Ca? Are those calculated by you?

If you are looking for sets of already available parameters, then you have to look for force fields that describe all the molecules you need. I am pretty sure CHARMM36 will probably have all these chemical species you cite, and probably other popular force fields as well. However, if you are interested in salt solutions (so on very good ion descriptions), these force fields might not be great, as they are tuned more on the bio side, focusing on proteins/lipids/nucleic acids and so on. I would suggest you to look in the literature for works that specifically fine tuned small force fields for just the handful of molecules you need!

3

What I meant was that I can get the parameters for Ca from CHARMM but was not sure of that of CO3, SO4 and HCO3

4

For sure there is CO3 and I am pretty sure you can also parametrize HCO3. Regarding SO4, I do not know!

5

Thanks obZehn