A reaction route network for methanol decomposition on a Pt(111) surface.

A reaction route network for the decomposition reaction of methanol on a Pt(111) surface was constructed by using the artificial force-induced reaction (AFIR) method, which can search for reaction paths automatically and systematically. Then, the network was kinetically analyzed by applying the rate constant matrix contraction (RCMC) method. Specifically, the time hierarchy of the network, the time evolution of the population initially given to CH3 OH to the other species on the network, and the most favorable route from CH3 OH to major and minor products were investigated by the RCMC method. Consistently to previous studies, the major product on the network was CO+4H, and the most favorable route proceeded through the following steps: CH3 OH → CH2 OH+H → HCOH+2H → HCO+3H → CO+4H. Furthermore, paths to byproducts found on the network and their kinetic importance were discussed. The present procedure combining AFIR and RCMC was thus successful in explaining the title reaction without using any information on its product or the reaction mechanism.

Understanding CO oxidation on the Pt(111) surface based on a reaction route network.

Analysis of a reaction on a solid surface is an important task for understanding the catalytic reaction mechanism. In this study, we studied CO oxidation on the Pt(111) surface by using the artificial force induced reaction (AFIR) method. A systematic reaction path search was done, and the reaction route network was created. This network included not only bond rearrangement paths but also migration paths of adsorbed species. Then, the obtained network was analyzed using a kinetics method called rate constant matrix contraction (RCMC). It is found that the bottleneck of the overall reaction is the CO2 generation step from an adsorbed CO molecule and an O atom. This result is consistent with the Langmuir-Hinshelwood (LH) mechanism with O2 dissociation discussed in previous studies. The present procedure, i.e., construction of the reaction route network by the AFIR method followed by application of the RCMC kinetics method to the resultant reaction route network, was fully systematic and uncovered two aspects: the impact of the existence of multiple paths in each bond rearrangement step and an entropic contribution arising from short-range migration of adsorbed species.

Implementation and performance of the artificial force induced reaction method in the GRRM17 program.

This article reports implementation and performance of the artificial force induced reaction (AFIR) method in the upcoming 2017 version of GRRM program (GRRM17). The AFIR method, which is one of automated reaction path search methods, induces geometrical deformations in a system by pushing or pulling fragments defined in the system by an artificial force. In GRRM17, three different algorithms, that is, multicomponent algorithm (MC-AFIR), single-component algorithm (SC-AFIR), and double-sphere algorithm (DS-AFIR), are available, where the MC-AFIR was the only algorithm which has been available in the previous 2014 version. The MC-AFIR does automated sampling of reaction pathways between two or more reactant molecules. The SC-AFIR performs automated generation of global or semiglobal reaction path network. The DS-AFIR finds a single path between given two structures. Exploration of minimum energy structures within the hypersurface in which two different electronic states degenerate, and an interface with the quantum mechanics/molecular mechanics method, are also described. A code termed SAFIRE will also be available, as a visualization software for complicated reaction path networks. © 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.