Force Field Atom types

The force field atom types are the labels given to each atom in the real system that is used to generate the molecular mechanics portion of the QM/MM potential. These are separate from the atomic fragment types used by ADF for the electronic structure calculation. It is important to realize that QM atoms will have both an atomic fragment type and a force field atom type.

There are some limitations to the force field label types that the user can specify:

• Labels can be a maximum of four characters long, with no spaces.
• The atom types are case sensitive.
• They can contain letters, numbers and other characters except ',' '.' or '=' and tabs.

Example of atom types that are not compatible with the program: C.3, C 3, C=3, C_sp3, *

Examples of atom types that are correct: C_3, C3, Csp3, and C*