Vibrationally inelastic H + D2 collisions are forward-scattered
Noah T Goldberg1, Jianyang Zhang, Konrad Koszinowski
1Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Summary
We measured differential cross sections for hydrogen atom collisions with deuterium molecules. Quantum mechanical calculations reveal universally forward-scattered products in vibrationally inelastic scattering, contrary to traditional models.
Area of Science:
- Chemical Physics
- Quantum Mechanics
- Molecular Dynamics
Background:
- Understanding molecular collisions is crucial for chemical reactions.
- Vibrational energy transfer in H + D2 scattering is a key benchmark system.
- Previous models predicted backward scattering for inelastic collisions.
Purpose of the Study:
- To measure differential cross sections for H + o-D2 inelastic scattering.
- To investigate the role of quantum mechanics in vibrationally inelastic collisions.
- To explain the observed forward-scattering phenomenon.
Main Methods:
- Experimental measurement of differential cross sections (DCSs).
- Theoretical quantum mechanical (QM) calculations.
- Comparison with quasiclassical trajectory (QCT) calculations.
Main Results:
- Products are dominantly forward-scattered across various collision energies and quantum states.
- QM calculations show excellent agreement with experimental DCSs.
- Forward-scattering is a universal feature of H + D2 vibrationally inelastic collisions.
Conclusions:
- The conventional textbook mechanism does not explain the observed scattering.
- Vibrational inelasticity in H + D2 is driven by a frustrated reaction mechanism.
- Quantum mechanical calculations accurately describe the dynamics of this system.
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