China News Agency, Dalian, Liaoning, May 7 (Reporter Yang Yi) At present, astronomers have observed oxygen in the atmosphere of a few planets such as the Earth, but the industry has been controversial about its source.
The Dalian Institute of Chemical Physics of the Chinese Academy of Sciences announced on the 7th that its researchers found that early oxygen on planets may come from the photolysis of water molecules, which is of great significance to the search for living planets.
The team of researchers Yuan Kaijun and Academician Yang Xueming, in collaboration with Nanjing University professor Xie Daiqian, discovered that water molecules can dissociate into three bodies under extreme ultraviolet light to produce oxygen atoms. Two oxygen atoms combine to form oxygen molecules, which is the source of oxygen in the planet’s early atmosphere. Origin provides new ideas.
Related research results were published in "Nature-Communication" and were recommended as a highlight article.
Previously, there was a view that oxygen is mainly produced by carbon dioxide (CO2) photochemistry, that is, carbon monoxide and oxygen atoms are generated by photodissociation of carbon dioxide, and two oxygen atoms recombine to generate oxygen.
Recent astronomical observations have found that there is a large amount of oxygen and water in the atmosphere of comet 67P, and the concentration of the two has a strong correlation.
The research community believes that the formation of oxygen in comets may be related to water, but the relevant mechanism is not clear.
Yuan Kaijun's team used the "Dalian Light Source", the first large-scale free electron laser scientific research user device independently developed by China, to systematically study the process of water molecule photochemistry.
The research team shortened the dissociation wavelength to 90-110 nanometers, irradiated water molecules, and found that three-body dissociation occurred, producing one oxygen atom and two hydrogen atoms.
The team members speculate that the recombination of two oxygen atoms to produce oxygen may be an important source of oxygen in these environments.
Combining the radiation intensity of early sunlight and the absorption spectrum analysis of water molecules, it is found that the probability of photolysis of water molecules to produce oxygen atoms is about 20%.
Yuan Kaijun said that water is abundant in cosmic nebulae, comet atmospheres, and the atmosphere of the early earth. The trisomy dissociation process of water molecules directly connects oxygen and water, which is of great significance to the search for living planets.
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