Methane dissociation on Ni(111): A seven-dimensional to nine-dimensional quantum dynamics study
Xiangjian Shen1, Zhaojun Zhang2, Dong H Zhang2
1Research Center of Heterogeneous Catalysis and Engineering Sciences, School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou 450001, China.
The Journal of Chemical Physics
|July 17, 2017
Summary
Quantum dynamics simulations reveal how methane
Area of Science:
- Surface Science and Physical Chemistry
- Computational Chemistry and Quantum Dynamics
Background:
- Methane (CH4) dissociation on Nickel (Ni(111)) is a benchmark reaction for understanding gas-surface interactions.
- Investigating the influence of reactant degrees of freedom (DOF) is crucial for accurate quantum dynamics simulations of C-H bond dissociation.
Purpose of the Study:
- To quantitatively explore the role of methane's CH stretching degree of freedom and azimuthal orientation in its dissociation on Ni(111).
- To develop and apply high-dimensional quantum dynamics models for gas-surface reactions.
Main Methods:
- Performed seven- to nine-dimensional (9D) quantum dynamics simulations.
- Utilized a recently developed fifteen-dimensional (15D) ab initio potential energy surface for Ni(111).
- Improved post-treatment models for surface impact site effects using a linear relationship for effective potential barriers.
Main Results:
- Sticking probabilities (S0) of ground state CH4 are weakly enhanced by the CH stretching DOF but significantly weakened by azimuthal orientation.
- The CH stretching DOF has a minor positive impact on sticking probabilities.
- Azimuthal orientation strongly influences the dissociation probability, reducing it significantly.
Conclusions:
- The CH stretching and azimuthal DOFs play distinct and significant roles in methane dissociation on Ni(111).
- The developed quantum dynamics models and improved post-treatment methods offer a robust framework for studying complex gas-surface reactions.
- These findings provide insights into the fundamental mechanisms governing catalytic reactions involving methane.
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