Reducing to Type-based Parameters

The reduce statement allows one to reduce the current parameters (atom-based as well as type-based) to type-based parameters using the CHEMical atom properties (Section 4.5). Each type-based equilibrium constant is obtained as an average of all instances of that type of interaction (bond, bond angle, dihedral angle, or improper angle) in the molecular structure. The energy constants can be obtained as a simple average or from the same statistical analysis (Eq. 3.1) as that used for the learn statement. The latter option is useful only when several instances of the same type-based interaction occur in the molecular structure. If there is only one instance or the variance is zero, the “reduced" energy constant is set to 999999. The periodicities ($n$) of dihedral and improper angles have to be consistent for all instances of atom-based parameters; otherwise a warning message will occur. The “reduced" periodicities are taken directly from the atom-based parameters. The reduce statement affects parameters only for those interaction terms that are turned on by the flags statement (Section 4.5).

Xplor-NIH 2024-06-11