AMBER forcefield

This page contains information about the AMBER forcefield. See the AMBER package for information about the computer code.

AMBER forcefield .

Force field

$E_{\rm {total}}=\sum _{\rm {bonds}}K_{r}(r-r_{eq})^{2}+\sum _{\rm {angles}}K_{\theta }(\theta -\theta _{eq})^{2}+\sum _{\rm {dihedrals}}{V_{n} \over 2}[1+{\rm {cos}}(n\phi -\gamma )]+\sum _{i<j}\left[{A_{ij} \over R_{ij}^{12}}-{B_{ij} \over R_{ij}^{6}}+{q_{i}q_{j} \over \epsilon R_{ij}}\right]+\sum _{\rm {H-bonds}}\left[{C_{ij} \over R_{ij}^{12}}-{D_{ij} \over R_{ij}^{10}}\right]$

Parameters

ff99

Param99 was developed for organic and biological molecules using the restrained electrostatic potential (RESP) approach to derive the partial charges:

ff02

The ff02 force field is a polarisable variant of ff99. The charges were determined at the B3LYP/cc-pVTZ//HF/6-31g* level, and hence are more like "gas-phase" charges.

External links

• AMBER parameters