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Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
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Mode specific dynamics in the H2 + SH → H + H2S reaction.
Dandan Lu1, Ji Qi2, Minghui Yang2
1School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China. jli15@cqu.edu.cn.
Physical Chemistry Chemical Physics : PCCP
|October 13, 2016
Summary
Vibrational excitation of hydrogen (H₂) significantly boosts the H₂ + SH reaction rate. Rotational excitation of H₂ has a minor effect, while SH excitation is negligible, revealing key reaction dynamics.
Area of Science:
- Chemical Dynamics
- Quantum Mechanics
- Reaction Kinetics
Background:
- Understanding reaction dynamics is crucial for controlling chemical processes.
- Mode-specific effects, where specific molecular vibrations or rotations influence reaction outcomes, are key areas of study.
- The H₂ + SH reaction serves as a model system for investigating these dynamics.
Purpose of the Study:
- To investigate the mode-specific dynamics of the H₂ + SH → H + H₂S reaction.
- To determine the influence of vibrational and rotational excitation of reactants on reaction enhancement.
- To rationalize the observed mode selectivity using theoretical models.
Main Methods:
- Full-dimensional coupled-channel quantum scattering calculations.
- Quasi-classical trajectory calculations.
- Utilizing accurate ab initio global potential energy surfaces based on coupled cluster level calculations and neural network representations.
Main Results:
- Strong mode selectivity was observed in the H₂ + SH reaction.
- Vibrational excitation of H₂ significantly enhances reactivity.
- Rotational excitation of H₂ shows a slight promotion of the reaction, while excitation of SH has a negligible effect.
- The sudden vector projection model partially explains the observed mode selectivity.
Conclusions:
- The vibrational state of H₂ is a critical factor in controlling the H₂ + SH reaction rate.
- The SH molecule acts largely as a spectator during the reaction.
- Theoretical calculations provide valuable insights into the mode-specific control of chemical reactions.
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