Simple Potential Functions
Functional forms for simple additional potentials
Below are listed the interaction forms available for simple 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 $r = r_{i} - r_{origin}$.
| Keyword | Parameters | Description |
|---|---|---|
Harmonic |
k |
Simple harmonic well potential$$ E_{ij} = \frac{1}{2} k r^2 $$ $$ F_{ij} = -k r $$ |
LJ |
$\epsilon$$\sigma$ |
Standard Lennard-Jones 12-6 potential. $$ 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. |