Directional Potential Functions
Functional forms for simple additional potentials
Below are listed the interaction forms available for directional additional potentials acting on individual atoms. All functional forms have an implied origin / reference coordinate defined by some other means (e.g. specified when adding additional potentials to configurations) with $r = r_{i} - r_{origin}$, as well as a directional vector component $v$ which defines the interaction.
| Keyword | Parameters | Description |
|---|---|---|
LJ |
$\epsilon$$\sigma$ |
Cylindrical Lennard-Jones 12-6 potential acting perpendicular to $v$. $$ E = 4 \epsilon \left( \left(\frac{\sigma}{r}\right)^{12} - \left(\frac{\sigma}{r}\right)^6 \right) $$ $$ F = -48 \epsilon \left( \frac{\sigma^{12}}{r^{13}} - \frac{1}{2} \frac{\sigma^6}{r^7} \right) $$ $epsilon$ and $sigma$ are used as-is and are not combined with the target atom’s parameters. |