Lyman alpha emission line

From Glossary of Meteorology



Lyman alpha emission line

Feature in the emission spectrum of solar radiation, identified with neutral hydrogen, that occurs at a wavelength of 121.567 nm. Because of the extremely low absorption cross section of molecular oxygen at this particular wavelength, this radiation penetrates deep into the earth's atmosphere. It is important to the dissociation of trace gases in the upper mesosphere and to the formation of the lower ionospheric layers by ionizing certain minor atmospheric constituent gases, especially nitric oxide.


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