OPLS
E ( r N ) = E b o n d s + E a n g l e s + E d i h e d r a l s + E n o n b o n d e d E b o n d s = ∑ b o n d s K r ( r − r 0 ) 2 E a n g l e s = ∑ a n g l e s k θ ( θ − θ 0 ) 2 E d i h e d r a l s = V 1 2 [ 1 + cos  ( φ − φ 0 ) ] + V 2 2 [ 1 − cos  2 ( φ − φ 0 ) ] + V 3 2 [ 1 + cos  3 ( φ − φ 0 ) ] + V 4 2 [ 1 − cos  4 ( φ − φ 0 ) ] E n o n b o n d e d = ∑ i > j f i j ( A i j r i j 12 − C i j r i j 6 + q i q j e 2 4 π ε 0 r i j ) {\displaystyle {\begin{aligned}E\left(r^{N}\right)&=E_{\mathrm {bonds} }+E_{\mathrm {angles} }+E_{\mathrm {dihedrals} }+E_{\mathrm {nonbonded} }\\E_{\mathrm {bonds} }&=\sum _{\mathrm {bonds} }K_{r}(r-r_{0})^{2}\\E_{\mathrm {angles} }&=\sum _{\mathrm {angles} }k_{\theta }(\theta -\theta _{0})^{2}\\E_{\mathrm {dihedrals} }&={\frac {V_{1}}{2}}\left[1+\cos(\phi -\phi _{0})\right]+{\frac {V_{2}}{2}}\left[1-\cos 2(\phi -\phi _{0})\right]+{\frac {V_{3}}{2}}\left[1+\cos 3(\phi -\phi _{0})\right]+{\frac {V_{4}}{2}}\left[1-\cos 4(\phi -\phi _{0})\right]\\E_{\mathrm {nonbonded} }&=\sum _{i>j}f_{ij}\left({\frac {A_{ij}}{r_{ij}^{12}}}-{\frac {C_{ij}}{r_{ij}^{6}}}+{\frac {q_{i}q_{j}e^{2}}{4\pi \epsilon _{0}r_{ij}}}\right)\end{aligned}}}