ReaxFF Engine Features Vs. Old Standalone Program

Introduction

Starting with AMS2018, ReaxFF is an engine for the AMS driver, thus sharing many of the features and input syntax with the other engines in the Amsterdam Modeling Suite.

Before AMS2018, ReaxFF was run as a standalone program. The older standalone program (“Old ReaxFF”) can still be run from the command-line, also in AMS2020. Some features are only available in this older program.

See also

Old Standalone ReaxFF manual

The engine shares all core routines with the standalone program, guaranteeing identical energies and forces between these two codes.

Feature comparison

Some features of the old standalone ReaxFF program have been implemented into the AMS driver, others into the ReaxFF engine, and some are currently not available in the new implementation. The table below indicates how certain features can be activated.

Feature New implementation Old implementation
0D, 1D, 2D periodicity AMS driver not available
ACKS2 force field file old manual entry
Adsorption analysis AMS driver old manual entry
Bond boost AMS driver old manual entry
ChemTraYzer AMS utilities old manual entry
CMAES FF optimizer ParAMS old manual entry
CVHD AMS driver old manual entry
Elastic wall restraint not available old manual entry
eReaxFF force field file old manual entry
External electric fields AMS driver old manual entry
Force-bias Monte Carlo AMS driver old manual entry
Force field parametrization ParAMS old manual entry
Grand-canonical Monte Carlo AMS driver old manual entry
Local atomic temperature not available old manual entry
LG dispersion force field file old manual entry
Molecular charge constraints ReaxFF Engine old manual entry
Molecule gun AMS driver old manual entry
NEMD (thermal conductivity) AMS driver old manual entry
Per-atom stress tensor not available old manual entry
Tapered bond orders ReaxFF engine old manual entry
Temperature profile along axis AMS driver old manual entry
Volume regimes AMS driver vregime.in Training Course

Differences in execution

To run ReaxFF as an AMS engine (recommended), run the ams executable and specify Engine ReaxFF:

"$AMSBIN"/ams <<EOF
    # ams input
    Engine ReaxFF
       ForceField CHO.ff
    EndEngine
EOF

To run ReaxFF as a standalone program (not recommended unless necessary), run the reaxff executable. The files control, geo, etc., must exist in the current working directory. For more information, see the Old ReaxFF manual.

"$AMSBIN"/reaxff