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Chlorine interactions with water ice studied by molecular beam techniques
Liza S E Romero Lejonthun1, Patrik U Andersson, Mats B Någård
1Department of Chemistry, Atmospheric Science, Göteborg University, SE 41296 Göteborg, Sweden.
The Journal of Physical Chemistry. B
|November 17, 2006
Summary
Chlorine molecule (Cl2) interactions with ice surfaces were investigated. Cl2 exhibits high trapping probability and rapid desorption, with binding energies stronger than previously thought.
Area of Science:
- Physical Chemistry
- Surface Science
- Atmospheric Chemistry
Background:
- Chlorine interactions with ice are crucial for stratospheric ozone depletion.
- Understanding these interactions requires detailed kinetic studies.
Purpose of the Study:
- To investigate the kinetics of chlorine molecule (Cl2) interactions with ice surfaces.
- To determine Cl2 binding energies and surface residence times on ice.
Main Methods:
- Molecular beam techniques were employed to study Cl2 interactions with ice.
- Experiments were conducted at temperatures ranging from 103 K to 165 K.
Main Results:
- Cl2 trapping probability was found to be unity at thermal incident energies.
- Desorption kinetics followed the Arrhenius equation, yielding activation energies of 0.24 ± 0.03 eV and 0.31 ± 0.01 eV.
- At least two distinct Cl2 binding sites on the ice surface were identified.
Conclusions:
- Cl2-ice binding energies are likely higher than previously estimated by theoretical models.
- The surface coverage of Cl2 on ice under stratospheric conditions is negligible.
- Results provide insights into heterogeneous chemical processes in the atmosphere.
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