In addition to files specified in the FF Optimizer section the following files must be present in the directory where the reaxff program is executed.
- iopt – file containing a single text line with 4 on it. This will instruct reaxff to perform a Monte-Carlo force-field optimization.
- ffield_min – minimum values for each force-field value (this file has the same format as ffield).
- ffield_max – maximum values for each force-field value (this file has the same format as ffield).
The mcffopt_water example in the examples/reaxff directory demonstrates the use of the MCFFOptimizer. Note however that this example is not physically meaningful. For example, many atomic force-field parameters are allowed to vary in a very broad range, which is the same for all elements. In practice, you will want to set the range for each element separately.