COnstraint GEometry to simulate Forces

COGEF is a package that contains tools for simulating force-induced bond-breaking reactions based on the COnstrained Geometries simulate External Force (COGEF) method (Beyer, M. K. J. Chem. Phys. 2000, 112, 7307). The package is based on the atomic simulation environment (ASE).

This module can be used to answer the question: How much force is needed to break a bond in a molecule? In a first step the maximum force can be obtained from the maximum slope of the energy-extension curve when the end-to-end distance of the molecule is stretched. In further steps, more precise rupture forces in dependence of the loading rate can be obtained by including the effects of temperature, a two-dimensional investigation of the energy landscape, multiple transitions into broken molecule forms and back reactions from the broken into the intact form. Furthermore polymer effects and the spring effect of a cantilever can be included to simulate force-extension curves from atomic force microscopy experiments with constant pulling velocity.