Construction of a Potential Energy Surface
Based on a Diabatic Model for
Proton Transfer in Molecular Pairs
Yuta Hori, Tomonori Ida and Motohiro Mizuno
Abstract We propose a simple construction method of the potential energy surface
based on diabatic model for proton transfer in molecular pairs. Assuming two-state
valence bond electronic wave functions as a diabatic basis, the diagonal and
non-diagonal matrix elements in diabatic potential of water, ammonia, and imidazole pairs were obtained. The validity of the construction procedure was confirmed
by comparing two adiabatic potentials: one was transformed from the obtained
diabatic potential and another was calculated by DFT calculation. Diabatic potentials were also obtained using fewer reference points than conventional methods at
various intermolecular distances. Finally, we discuss the resulting diabatic potential
and non-diagonal elements in detail.
Keywords Potential energy surface ⋅ Proton transfer ⋅ Diabatic
1 Introduction
One of the important steps in the theoretical treatment of chemical reactions is
representation of the potential energy surface (PES) [1, 2]. Most approaches to
chemical reactions analyze the PES by quantum chemical calculations derived
under the Born-Oppenheimer approximation, also known as the adiabatic PES.
Once the adiabatic potential is obtained, the scattering cross section, reaction
constant, and reaction path, which are important for understanding chemical reactions, can be obtained from the potential [3]. Though ab initio quantum chemical
calculations are becoming possible for large molecular systems, however, accurate
PES calculations for understanding chemical reaction tend to be unfeasible. In
addition, though analytical function for PES requires to analyze the reaction, the
global function has not been known.
Y. Hori ( ✉ ) ⋅ T. Ida ⋅ M. Mizuno
Chemistry Course, Division of Material Chemistry, Graduate School of Natural
Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
e-mail: yu.hori59@gmail.com
© Springer International Publishing AG, part of Springer Nature 2018
Y. A. Wang et al. (eds.), Concepts, Methods and Applications of Quantum Systems
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 31,
https://doi.org/10.1007/978-3-319-74582-4_9
179
Based on a Diabatic Model for
Proton Transfer in Molecular Pairs
Yuta Hori, Tomonori Ida and Motohiro Mizuno
Abstract We propose a simple construction method of the potential energy surface
based on diabatic model for proton transfer in molecular pairs. Assuming two-state
valence bond electronic wave functions as a diabatic basis, the diagonal and
non-diagonal matrix elements in diabatic potential of water, ammonia, and imidazole pairs were obtained. The validity of the construction procedure was confirmed
by comparing two adiabatic potentials: one was transformed from the obtained
diabatic potential and another was calculated by DFT calculation. Diabatic potentials were also obtained using fewer reference points than conventional methods at
various intermolecular distances. Finally, we discuss the resulting diabatic potential
and non-diagonal elements in detail.
Keywords Potential energy surface ⋅ Proton transfer ⋅ Diabatic
1 Introduction
One of the important steps in the theoretical treatment of chemical reactions is
representation of the potential energy surface (PES) [1, 2]. Most approaches to
chemical reactions analyze the PES by quantum chemical calculations derived
under the Born-Oppenheimer approximation, also known as the adiabatic PES.
Once the adiabatic potential is obtained, the scattering cross section, reaction
constant, and reaction path, which are important for understanding chemical reactions, can be obtained from the potential [3]. Though ab initio quantum chemical
calculations are becoming possible for large molecular systems, however, accurate
PES calculations for understanding chemical reaction tend to be unfeasible. In
addition, though analytical function for PES requires to analyze the reaction, the
global function has not been known.
Y. Hori ( ✉ ) ⋅ T. Ida ⋅ M. Mizuno
Chemistry Course, Division of Material Chemistry, Graduate School of Natural
Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
e-mail: yu.hori59@gmail.com
© Springer International Publishing AG, part of Springer Nature 2018
Y. A. Wang et al. (eds.), Concepts, Methods and Applications of Quantum Systems
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 31,
https://doi.org/10.1007/978-3-319-74582-4_9
179