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.
Last modified April 23, 2024: Update release notes. (70ff745)