CaO-water reaction using reaxff

Hi Chamara,

Thanks for the response. Yes, I used the NPT ensemble, but that didn’t work. In the paper, first, they equilibrate the CaO slab with vacuum space on NPT for 50 ps. I did the same. Then I input water molecules using packmole and simulate the whole system with NVT as mentioned in the paper. Previously attached files are for the 2nd simulation.

Kind regards,
Udeshini

Then I guess it needs expertise on ReaxxFF. I have worked on some classical water models (not Reax) and what I experienced was when we randomly throw water molecules in a volume, roughly matching the density of water and run it in nvt, then the system is unable to relax (if water molecules are far apart -> creates negative pressure, if water molecules are too close -> creates very high positive pressure) due to the constant volume of nvt ensemble and so system tends to misbehave. That was my guess on your issue in a general point of view. You may able to check whether the system is relaxed or not by monitoring the pressure. if it’s too high or too negative, “not good”. Hope you could get something from my experience to handle your issue.

Chamara

Hi Chamara,

Thanks a lot for your suggestions. I think the system is not well equilibrated.

Kind regards,
Udeshini