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Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System
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Probing Nonadiabatic Effects in Low-Energy C(3 P j) + H2 Collisions
Jacek Kłos1, Astrid Bergeat2, Gianmarco Vanuzzo2,3
1Department of Chemistry and Biochemistry , University of Maryland , College Park , Maryland 20742-2021 , United States.
The Journal of Physical Chemistry Letters
|October 31, 2018
Summary
This study details the spin-orbit excitation of carbon atoms by molecular hydrogen, crucial for understanding interstellar cloud chemistry. Accurate measurements and quantum calculations confirm the dynamics, impacting abundance and cooling estimates.
Area of Science:
- Chemical Physics
- Quantum Dynamics
- Astrochemistry
Background:
- Nonadiabatic effects and spin-orbit couplings govern energy transfer in inelastic collisions.
- Collisions involving open-shell atoms like carbon are key to understanding complex chemical processes.
Purpose of the Study:
- Investigate the spin-orbit excitation of ground-state carbon atoms (C(3Pj=0)) by molecular hydrogen (H2) at low energies.
- Provide accurate state-to-state integral cross sections and rate coefficients for astrochemical modeling.
- Enhance the understanding of nonadiabatic dynamics in atomic-molecule collisions.
Main Methods:
- Experimental crossed-beam studies using a pure beam of C(3Pj=0).
- Highly accurate quantum mechanical calculations.
- Determination of state-to-state integral cross sections and rate coefficients.
Main Results:
- Excellent agreement between experimental and theoretical cross sections.
- Demonstrated ability to accurately model nonadiabatic dynamics.
- New rate coefficients provided for temperatures relevant to interstellar clouds.
Conclusions:
- The study validates theoretical models for nonadiabatic collision dynamics.
- Findings will refine estimates of atomic carbon abundance in interstellar clouds.
- The efficiency of interstellar gas cooling by carbon atoms is re-evaluated.
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