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In physics and chemistry, the Lyman series is a hydrogen spectral series of transitions and resulting ultraviolet emission lines of the hydrogen atom as an electron goes from n ≥ 2 to n = 1 (where n is the principal quantum number), the lowest energy level of the electron (groundstate).
The Lyman-alpha forest was first discovered in 1970 by astronomer Roger Lynds in an observation of the quasar 4C 05.34. [1] Quasar 4C 05.34 was the farthest object observed to that date, and Lynds noted an unusually large number of absorption lines in its spectrum and suggested that most of the absorption lines were all due to the same Lyman-alpha transition. [2]
For example, the 2 → 1 line is called "Lyman-alpha" (Ly-α), while the 7 → 3 line is called "Paschen-delta" (Pa-δ). Energy level diagram of electrons in hydrogen atom. There are emission lines from hydrogen that fall outside of these series, such as the 21 cm line.
Lyman-alpha, typically denoted by Ly-α, is a spectral line of hydrogen (or, more generally, of any one-electron atom) in the Lyman series. It is emitted when the atomic electron transitions from an n = 2 orbital to the ground state ( n = 1), where n is the principal quantum number .
The Lyman alpha line is the n=2 to n=1 transition of neutral hydrogen, and can be produced copiously by galaxies with young stars. [14] Moreover, Lyman alpha photons interact strongly with neutral hydrogen in intergalactic gas through resonant scattering, wherein neutral atoms in the ground (n=1) state absorb Lyman alpha photons and almost ...
The hydrogen line is produced when an electron in a neutral hydrogen atom is excited to the triplet spin state, or de-excited as the electron and proton spins go to the singlet state. The energy difference between these two hyperfine states is 5.9 × 10 − 6 {\displaystyle 5.9\times 10^{-6}} electron volts , with a wavelength of 21 centimeters.
A hydrogen molecule can absorb a far-ultraviolet photon (11.2 eV < energy of the photon < 13.6 eV) and make a transition from the ground electronic state X to excited state B (Lyman) or C (Werner). Radiative decay occurs rapidly. 10–15% of the decays occur into the vibrational continuum. This means that the hydrogen molecule has dissociated.
Lyman-alpha blob 1 (LAB-1) is a giant cosmic cloud of gas located in the constellation of Aquarius, approximately 11.5 billion light-years from Earth with a redshift (z) of 3.09. It was discovered unexpectedly in 2000 by Charles Steidel and colleagues, [ 2 ] who were surveying for high- redshift galaxies using the 200 inch (5.08 m) Hale ...