Fueled by advances in hardware and algorithm design,
large-scale
automated explorations of chemical reaction space have become possible.
Here, we present our approach to an open-source, extensible framework
for explorations of chemical reaction mechanisms based on the first-principles
of quantum mechanics. It is intended to facilitate reaction network
explorations for diverse chemical problems with a wide range of goals
such as mechanism elucidation, reaction path optimization, retrosynthetic
path validation, reagent design, and microkinetic modeling. The stringent
first-principles basis of all algorithms in our framework is key for
the general applicability that avoids any restrictions to specific
chemical systems. Such an agile framework requires multiple specialized
software components of which we present three modules in this work.
The key module, Chemoton, drives the exploration of reaction
networks. For the exploration itself, we introduce two new algorithms
for elementary-step searches that are based on Newton trajectories.
The performance of these algorithms is assessed for a variety of reactions
characterized by a broad chemical diversity in terms of bonding patterns
and chemical elements. Chemoton successfully recovers the
vast majority of these. We provide the resulting data, including large
numbers of reactions that were not included in our reference set,
to be used as a starting point for further explorations and for future
reference.