Simulation of saltwater droplet on a surface

Science Talk
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Hello everyone. I am currently working on simulating a saltwater droplet on a silicon surface and calculating its contact angle. Initially, I successfully simulated a pure water droplet using the SPC/E water model and obtained an 86.8 contact angle, which aligns with previous studies. However, when adding NaCl salt to the droplet to increase the salt concentration, the contact angle decreased instead of increasing, contrary to what has been reported in the literature. In other words, the droplet spread more on the surface. I think the problem is the interaction parameters I used. The literature uses different Lennard Jones interaction parameters for NaCl, and I have been struggling to determine which parameters are true. For reference, I have attached the papers I used to extract the atom interactions as well as a portion of my input file to provide you with more intuition for my simulation. I would greatly appreciate any assistance in resolving this problem.
I had a similar problem while simulating a pure water droplet because of the different interaction parameters suggested in the literature. Eventually, I could obtain favorable results by using the attached paper (Song’s paper).

interaction parameters
interaction parameters1069Ă—536 127 KB

song2013.pdf (3.5 MB)
reagan1999.pdf (118.6 KB)

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@passenger I have re-categorized your post to the “Science Talk” since, outside of using LAMMPS to simulate your system, there is nothing specific to LAMMPS in here and you want to discuss the science and not LAMMPS.

I would be very concerned about mixing and matching two different models from two different papers. Those two models may have very different balances between Coulomb and non-Coulomb interactions and that invalidate their use in combination.

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No, I didn’t combine the papers’ parameters. In fact, the authors of the first paper used the parameters from the second paper. I included the second paper to provide you with a more detailed understanding of the parameters and potentials.

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Well, then those authors made the same problematic choice. Lots of stuff gets published these days and as people are less and less experienced in how to properly parameterize potentials, they get increasingly casual in mixing and matching different functional forms and sets of parameters.

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Yes, I think so too. Because, unfortunately the parameters of many articles didn’t work for me.