3.2 Force Fields
Omega provides the facility for users to select one of a number of
pre-defined force fields. The force field selected may be different
for model construction and torsion search. The ability to select a
force field provides a mechanism for task specificity. Some force
fields may be more appropriate for solution phase ensemble generation,
whilst others may excel for bioactive conformer reproduction. The
following pre-defined force fields may be used as arguments to the
-buildff and searchff flags.
mmff- Exact reproduction of the published Merck Molecular
Force Field (MMFF)[14,15,16,17,18,19,20].
mmff_NoEstat- This force field variant includes all MMFF
terms except coulomb interactions.
mmff_Trunc- This force field variant excludes both
coulomb interactions and the attractive part of Van der Waals
interactions. All other components of the MMFF force field are
calculated according to literature specifications.
mmff94s- Exact reproduction of the 94s variant of the
Merck Molecular force Field (MMFF94s)[14,15,16,17,18,19,20].
mmff94s_NoEstat- This force field variant includes all
MMFF94s terms except coulomb interactions.
mmff94s_Trunc- This force field variant excludes both
coulomb interactions and the attractive part of Van der Waals
interactions. All other components of the MMFF94s force field are
calculated according to literature specifications.
