Connectivity changes were determined using a bond order threshold of 0.5 in ReaxFF, with a bond order close to 1.0 indicating a connected bond, and values approaching 0.0 representing broken bonds. In this study, the bond order threshold is used to estimate the position of the dividing surface (DS) that separates reactant and product states, and possible TS are assumed to be near this dividing surface. This way, CTY can provide an estimate of reaction activation energies even for barrierless reactions, i.e. reactions without a TS, through constrained minimization once a reaction geometry reaches the DS. During minimization, atoms involved in connectivity changes are fixed, allowing geometric changes due to reactions to be preserved while reducing thermal noise. To some extent this simple barrier estimation can help in an initial evaluation of the rate constant and therefore of the importance of a reaction found by CTY-TAD or PESmapping, before computationally demanding higher-level (quantum mechanical) optimizations are started. This way of estimating a reaction barrier is advantageous in that it is robust, in contrast to a proper TS search, which can be unsuccessful for a number of reasons.