Force Fields in TEAMFF

TEAMFF comes with multiple force fields in different force field types and coverages. These force fields are classified in three categories: basic, general and special.

Basic Force Fields

The purpose of basic force fields is for providing a starting point of further developments and optimizations.

The basic force fields are listed in the following table.

These force field were developed by fitting QM data of molecular fragments representing common organic molecules, drug-like molecules taken from MayBridge database and synthetic polymers taken from PolyInfo database. Quantum mechanics calculations were carried out at the level of B3LYP/6-31G(d,p). Atomic partial charges were derived by fitting the ESP charges. Parameterization was validated by comparing force field predicted data (e.g., vibrational frequencies; conformational energies; structural properties such as bond lengths, angles, dihedral angles, etc) against QM data. The LJ parameters are fixed to default values obtained by survey of literature.

General Force Fields

The general force fields are derived by refining and extending the basic force fields. The refinements include valence, charge and LJ parameters, according to extensive research results. [^1] In addition to the molecules covered by the Basic version, the new coverage includes

There are two force fields in this category: TEAM-General and AMBER-General, which service material and life sciences:

Both force fields are developed using the same typing rules, same optimized LJ-12-6 parameters, and similar QM data set.

Special Force Fields

The special force fields are developed to extend the coverage of general force fields, for specific application scopes, ionic liquids and zeolites.

These force fields, works together with the general force fields to expand the coverage without compromising the quality of parameters. More detail is given in extensibility of TEAMFF. Depending on the coverage scope, one or both types are developed.