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Updated: Nov 12, 2025
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Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
3.1K
Shape resonance determined from angular distribution in D2 (v = 2, j = 2) + He → D2 (v = 2, j = 0) + He cold
Haowen Zhou1, William E Perreault1, Nandini Mukherjee1
1Department of Chemistry, Stanford University, Stanford, California 94305, USA.
The Journal of Chemical Physics
|March 16, 2021
Summary
An l=2 shape resonance was observed in cold D2-He collisions, significantly impacting scattering dynamics. This finding reveals a strong D2-He interaction likely driven by an orbiting resonance.
Area of Science:
- Chemical Physics
- Molecular Collisions
- Quantum Mechanics
Background:
- Understanding molecular collisions is crucial for chemical reaction dynamics and energy transfer.
- Previous studies on D2-He collisions have not fully characterized resonance phenomena at low temperatures.
Purpose of the Study:
- To investigate the presence and characteristics of shape resonances in cold D2-He collisions.
- To analyze the influence of molecular alignment on collision dynamics.
- To compare the collision rates between D2-He and D2-D2 systems.
Main Methods:
- Utilized Stark-induced adiabatic Raman passage to prepare D2 molecules in specific rovibrational states (v=2, j=2).
- Employed magnetic sublevel selection to control the spatial orientation of the D2 bond axis.
- Measured angular distributions of scattered D2 molecules in collisions with He at approximately 1 K.
Main Results:
- Identified an l=2 shape resonance in the angular distribution of D2-He collisions.
- Observed that D2-D2 relaxation rates are nearly two orders of magnitude weaker than D2-He rates.
- Demonstrated control over molecular orientation influencing collision outcomes.
Conclusions:
- The observed resonance suggests a significant role for orbiting resonances in D2-He scattering.
- The long-range potential's shape is highly sensitive and dictates the strength of D2-He interactions.
- The stark difference in relaxation rates highlights the unique nature of D2-He interactions compared to D2-D2.
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