Adding Potentials

It may come to pass that you will need a potential other than the Buckingham potential already included. Fortunately, this program includes support for creating and adding arbitrary potentials.

For this, the potential style builder can either be found under Simulation > Create Potential Style:

Or it can be found in the simulation builder dialog for any of the LAMMPS-based simulations:

Once launched, you will be met with a dialog for creating a new potential style:

Style Builder

The first field needed is a name. Note that this name is arbitrary, and will not be seen by any of the simulators. However, this will be the name referred to in potential coefficient files.

Next, you will need to enter a name that the simulator would recognize. For example: buck/coul/long for LAMMPS. A complete list of LAMMPS potentials is available here.

Finally, you will need to declare all arguments your potential has:

Each argument requires a name, type, and default value. Additionally, no two arguments can have the same name. The type, meanwhile, can either be element, float, integer, or string:

Finally, each argument must be given a default value with a type that matches the aforementioned specified type.

Once finished, click "OK," and you will be prompted to save the potential style. In order for this new style to be automatically recognized by the program, it must be saved to /assets/simulation-builders/potential-defs/.

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File Format

Potential definitions are saved as a human-readable .json file. Here, several nested key-value pairs contain all the information that would've been entered above.

As an example, here is the definition for the default Buckingham potential:

{
    "name": "buck/coul/long (Two Atom)",
    "resolutions": {
        "LAMMPS": "buck/coul/long"
    },
    "arguments": {
        "Atom1": {
            "dtype": "element",
            "default": "Xx"
        },
        "Atom2": {
            "dtype": "element",
            "default": "Xx"
        },
        "A": {
            "dtype": "element",
            "default": 0.0
        },
        "ρ": {
            "dtype": "float",
            "default": 0.01
        },
        "C": {
            "dtype": "float",
            "default": 0.0
        }
    }
}