OPLS force field

The optimized potentials for liquid simulations (OPLS) force-field was developed for the simulation of proteins and other organic liquids.

OPLS-all atom

(OPLS-AA)

Form of the force field

Bond stretching

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{\rm {bond}} = \sum_{\rm {bonds}} K_r \left(r-r_{eq}\right)^2}

Angle bending

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{\rm {angle}} = \sum_{\rm {angles}} K_\theta \left(\theta-\theta_{eq}\right)^2}

Torsion

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E(\phi) = \frac{V_1}{2} \left[ 1 + \cos (\phi +f1)\right] + \frac{V_2}{2} \left[ 1 - \cos (2\phi +f2)\right] + \frac{V_3}{2} \left[ 1 + \cos (3\phi +f3)\right]}

Non-bonded

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{ab} = \sum_i^{\rm {on~a}}\sum_j^{\rm {on~b}} \left[ \frac{q_i q_j e^2}{r_{ij}} + 4\epsilon_{ij} \left( \frac{\sigma_{ij}^{12}}{r_{ij}^{12}}-\frac{\sigma_{ij}^{6}}{r_{ij}^{6}}\right)\right]f_{ij}, ~~~~f_{ij} = \left\{ \begin{array}{lll} 0.5 & ; & {\rm {if}}~~ i,j = 1,4 \\ 1 & ; & {\rm {otherwise}} \end{array} \right. }