Because of the spin–orbit interaction, the Lyman-alpha line splits into a fine-structure doublet with the wavelengths of 1215.668 and 1215.674 angstroms.[1] These components are called Ly-α3/2 and Ly-α1/2, respectively.
The eigenstates of the perturbedHamiltonian are labeled by the totalangular momentumj of the electron, not just the orbital angular momentuml. In the n = 2, l = 1 orbital, there are two possible states, with j = 1/2 and j = 3/2, resulting in a spectral doublet. The j = 3/2 state has a higher energy and so is energetically farther from the n = 1 state to which it is transitioning. Thus, the j = 3/2 state is associated with the more energetic (having a shorter wavelength) spectral line in the doublet.[2]
Observation
Since the hydrogen Lyman-alpha radiation is strongly absorbed by the air, its observation in laboratory requires use of vacuumed spectroscopic systems. For the same reason, Lyman-alpha astronomy is ordinarily carried out by satellite-borne instruments, except for observing extremely distant sources whose redshifts allow the line to penetrate the Earth atmosphere.
The line was also observed in antihydrogen.[3] Within the experimental uncertainties, the measured frequency is equal to that of hydrogen, in agreement with predictions of quantum electrodynamics.
^Kramida, Alexander; Ralchenko, Yuri (1999), NIST Atomic Spectra Database, NIST Standard Reference Database 78, National Institute of Standards and Technology, retrieved 2021-06-27
^Ahmadi, M.; et al. (22 August 2018). "Observation of the 1S–2P Lyman-α transition in antihydrogen". Nature. 560 (7720): 211–215. doi:10.1038/s41586-018-0435-1. PMC6786973. PMID 30135588.
January 22, 2023
lyman, alpha, line, typically, denoted, spectral, line, hydrogen, more, generally, electron, atom, lyman, series, emitted, when, atomic, electron, transitions, from, orbital, ground, state, where, principal, quantum, number, hydrogen, wavelength, 1215, angstro. The Lyman alpha line typically denoted by Ly a 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 In hydrogen its wavelength of 1215 67 angstroms 121 567 nm or 1 21567 10 7 m corresponding to a frequency of about 2 47 1015 Hz places Lyman alpha in the ultraviolet UV part of the electromagnetic spectrum More specifically Ly a lies in vacuum UV VUV characterized by a strong absorption in the air Contents 1 Fine structure 2 Observation 3 See also 4 ReferencesFine structure Edit The Lyman alpha doublet Because of the spin orbit interaction the Lyman alpha line splits into a fine structure doublet with the wavelengths of 1215 668 and 1215 674 angstroms 1 These components are called Ly a3 2 and Ly a1 2 respectively The eigenstates of the perturbed Hamiltonian are labeled by the total angular momentum j of the electron not just the orbital angular momentum l In the n 2 l 1 orbital there are two possible states with j 1 2 and j 3 2 resulting in a spectral doublet The j 3 2 state has a higher energy and so is energetically farther from the n 1 state to which it is transitioning Thus the j 3 2 state is associated with the more energetic having a shorter wavelength spectral line in the doublet 2 Observation EditSince the hydrogen Lyman alpha radiation is strongly absorbed by the air its observation in laboratory requires use of vacuumed spectroscopic systems For the same reason Lyman alpha astronomy is ordinarily carried out by satellite borne instruments except for observing extremely distant sources whose redshifts allow the line to penetrate the Earth atmosphere The line was also observed in antihydrogen 3 Within the experimental uncertainties the measured frequency is equal to that of hydrogen in agreement with predictions of quantum electrodynamics See also EditLyman alpha forest Lyman alpha emitter Lyman alpha blob Lyman break galaxy K alpha lineReferences Edit Kramida Alexander Ralchenko Yuri 1999 NIST Atomic Spectra Database NIST Standard Reference Database 78 National Institute of Standards and Technology retrieved 2021 06 27 Draine Bruce T 2010 Physics of the Interstellar and Intergalactic Medium Princeton N J Princeton University Press p 83 ISBN 978 1 4008 3908 7 OCLC 706016938 Ahmadi M et al 22 August 2018 Observation of the 1S 2P Lyman a transition in antihydrogen Nature 560 7720 211 215 doi 10 1038 s41586 018 0435 1 PMC 6786973 PMID 30135588 Retrieved from https en wikipedia org w index php title Lyman alpha line amp oldid 1064691429, wikipedia, wiki, book, books, library,
