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arXiv · 2607.11418

Efficient, direct calculation of reaction rate coefficients based on a partially rearranged rovibrational Hamiltonian. A full-dimensional case study of the H$_2$ + D $\rightarrow$ HD + H reaction

Gábor A. Ecseri·Attila G. Császár·Csaba Fábri
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Abstract

It is shown that an efficient, direct, and fully quantum mechanical calculation of thermal reaction rate coefficients requires a new, partially rearranged form of the numerically-constructed exact kinetic energy part of the rovibrational Hamiltonian expressed in internal coordinates. Using this Hamiltonian and an accurate, full-dimensional potential energy surface characterizing the H$_2$ + H exchange reaction, developed by Mielke, Garrett, and Peterson (J. Chem. Phys. 2002, 116, 4142), reaction rate coefficients in the temperature range of $75-800$ K have been computed for the H$_2$ + D $\rightarrow$ HD + H reaction. The paper puts particular emphasis on the exact treatment of overall molecular rotation and on nuclear spin symmetry.

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Gábor A. Ecseri, Attila G. Császár, Csaba Fábri. 2026-07-13. Efficient, direct calculation of reaction rate coefficients based on a partially rearranged rovibrational Hamiltonian. A full-dimensional case study of the H$_2$ + D $\rightarrow$ HD + H reaction. https://doi.org/10.1021/acs.jpca.6c01349

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