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Direct visualization of radiation-induced transformations at alkali halide-air interfaces
Shawn L Riechers1, Nikolay G Petrik2, John S Loring2
1Pacific Northwest National Laboratory, Richland, WA, USA. shawn.riechers@pnnl.gov.
Communications Chemistry
|January 25, 2023
Summary
This study reveals how X-rays transform mineral surfaces in air. Using advanced atomic force microscopy, researchers observed nanoscale reactions, providing new insights into atmospheric chemistry.
Area of Science:
- Environmental Science
- Materials Science
- Surface Chemistry
Background:
- Radiation-driven reactions at mineral/air interfaces impact atmospheric chemistry.
- Previous experimental limitations hindered a complete understanding of these processes.
Purpose of the Study:
- To investigate the in situ transformation of mineral surfaces under X-ray irradiation.
- To elucidate the nanoscale mechanisms of radiation-driven reactions at mineral/air interfaces.
Main Methods:
- Utilized a custom atomic force microscope with an integrated X-ray source for in situ nanoscale observation.
- Followed the transformation of potassium bromide surfaces to potassium nitrate.
Main Results:
- Observed direct in situ nanoscale transformation of potassium bromide to potassium nitrate.
- Identified radiolysis initiating step edge dissolution, surface evolution, and crystallite nucleation/growth.
- Demonstrated surface diffusion, controlled by adsorbed water, mediates growth rates.
Conclusions:
- Decoupling irradiation and observation provides valuable insights, unlike high-dose techniques.
- The study offers a novel approach to understanding radiation-driven surface reactions in atmospheric conditions.
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