77th CEMS Colloquium

Title

Global reaction route mapping by the artificial force induced reaction method: Toward systematic exploration of unknown chemical reactions

Abstract

One can elucidate the paths of chemical reactions through calculations of transition state structures by quantum chemical calculations. On the other hand, in actual chemical reactions, a huge number of intermediate and resting-state structures are involved. These stable and metastable structures form the so-called reaction path network. By analyzing such a reaction path network through a kinetic method, one can elucidate an entire picture of the underlying reaction process.

Here, it is the key to generate the reaction path network which includes all relevant intermediate and resting-state structures. We have developed the so-called artificial force induced reaction (AFIR) method [1,2]. The AFIR method searches for these structures automatically by inducing structural deformations in a given system systematically by adding artificial force between fragments in the system. The AFIR method is available in the GRRM17 program [3].

The AFIR method provides a complex reaction path network consisting of thousands or more of intermediate and resting-state structures. It is thus hard to extract relevant reaction paths from such a complex network. We, therefore, developed a kinetic method called the rate constant matrix contraction (RCMC) method [4]. The RCMC method systematically reduces the size of rate equations and allows one to extract the reaction mechanism automatically from a given reaction path network.

In my talk, I will discuss the automated generation of the complex reaction path network by the AFIR method and its systematic analysis by the RCMC method with some representative examples. Besides, I will present our recent attempts to find new chemical reactions from the reaction path networks.

[1] Maeda, S.; Morokuma, K. J. Chem. Phys. 2010, 132, 241102.
[2] Maeda, S.; Harabuchi, Y.; Takagi, M.; Taketsugu, T.; Morokuma, K. Chem. Rec. 2016, 16, 2232.
[3] Maeda, S.; Harabuchi, Y.; Takagi, M.; Saita, K.; Suzuki, K.; Ichino, T.; Sumiya, Y.; Sugiyama, K.; Ono, Y. J. Comput. Chem. 2018, 39, 233.
[4] Sumiya, Y.; Nagahata, Y.; Komatsuzaki, T.; Taketsugu, T.; Maeda, S. J. Phys. Chem. A 2015, 119, 11641.