Inquiry on Using MBX for Water Molecules in Silver Electrode System

[刘赵洋]

Dear developers and everyone,

I hope this email finds you well.

I am working on a simulation with a silver electrode and water molecules, where I aim to apply the MBX polarization force field only to the water molecules, while using Lennard-Jones for the silver electrode. I used the following command in LAMMPS: fix 2 water mbx 1 h2o 2 3 3 2 3 3 json mbx.json, but I encountered the error ERROR: The atom types in fix mbx do not match the atom types in the data file (../fix_mbx.cpp:458). After checking my data file, I confirmed that oxygen is assigned type 2 and hydrogen is assigned type 3, which matches the MBX settings. I would like to know if it is possible to apply MBX only to the water molecules, or if I need to include the silver electrode, and if so, can silver be assigned the dp1 monomer type or is there another way to handle silver in this setup?

Thank you for your time and I look forward to your suggestions.

Best regards,

Sibing Chen

 

[Henry Agnew]

Dear Sibing,
         Based on your question, it sounds like you are using a silver electrode in a simulation with MB-pol water molecules. If this is indeed correct, then yes you will need to perform a hybrid simulation using the dp1 monomer type for the silver electrode.

This setup has some similarities with our MOF+H2O example, where the MOF is treated using dp1 and coul/exclude. https://github.com/paesanilab/MBX/blob/master/plugins/lammps/examples/mof_ff_lammps%2B1_h2o_mbx/lammps.in

Since you are doing an electrode-based system, are you using the electrode with a constant charge or something fancier? MBX calculates all hybrid electrostatics internally using dp1, so it may not be compatible if you are doing something fancier.

Hopefully this answers your question, and let us know if you have any follow-up questions,

Best regards,
 The MBX Team