Researchers demonstrated that oxygen can be produced without the help of plants using a high energy vacuum ultraviolet laser to excite carbon dioxide.
About one-fifth of the Earth's atmosphere is made up of oxygen created by photosynthesis occurring in green plants, but researchers have wondered if some of this element existed 2.4 million years ago before photosynthesizing life first hit the scene, the University of California - Davis reported. These new findings support the idea that oxygen existed in the early atmosphere.
"Our results indicate that O2 can be formed by carbon dioxide dissociation in a one step process. The same process can be applied in other carbon dioxide dominated atmospheres such as Mars and Venus," said UC Davis graduate student Zhou Lu, working with professors in the Departments of Chemistry and of Earth and Planetary Sciences.
Zhou used a vacuum ultraviolet laser to irradiate CO2 in the laboratory. Vacuum ultraviolet light has a wavelength below 200 nanmoeters and is absorbed by air under natural conditions.
This one-step process could be happening right now in the Earth's atmosphere as carbon dioxide increases in the region of the upper atmosphere where high energy vacuum ultraviolet light from the Sun hits Earth or even other planets.
This is the first time this process has been had been demonstrated in a lab, so models of the evolution of planetary atmospheres will have to be readjusted to take the new findings into account.
The research was published in a recent edition of the journal Science.
Coauthors on the paper are, in the UC Davis Department of Chemistry, postdoctoral researcher Yih Chung Chang, Distinguished Professor Cheuk-Yiu Ng and Distinguished Professor emeritus William M. Jackson; and Professor Qing-Zhu Yin, Department of Earth and Planetary Sciences. The work was principally funded by NASA, NSF, and the U.S. Department of Energy.
