Astrophysics (Index)About

Lyman series

(L, Ly, Lyman lines)
(hydrogen series from electrons settling from n > 1 to n = 1)

The Lyman series is the set of emission lines (Lyman lines) from atomic hydrogen gas, due to electrons descending from an electron shell of number n greater than 1 down to that of n = 1, or the analogous absorption lines when absorbed electromagnetic radiation (EMR) makes electrons do the opposite. It is one of the hydrogen line series, such as the Balmer series, and is named after Theodore Lyman. The lines fall within extreme ultraviolet (EUV) and those produced by astronomical sources cannot be observed from the ground unless considerably redshifted. Lines:

Formula for the wavelengths:

1/wavelength = RH ( 1 - 1/n² )

Photons with wavelength at or shorter than the Lyman limit can ionize any neutral atomic hydrogen atom, and are termed Lyman continuum photons (LyC photons), thus they are likely to ionize any such hydrogen in clouds they pass through, regardless of whether the hydrogen is excited. Cases where photons, e.g., from a galaxy, avoid such absorption (Lyman continuum escape, LyC escape) are of research interest. The galaxies from which this occurred are termed Lyman continuum leakers (LyC leakers).

Hydrogen with neutrons (its other isotopes) have analogous series (i.e., a Lyman series, a Balmer series, etc.) that have slightly different wavelengths, as do other elements when ionized to the point that they have just one electron. Their series wavelengths can be calculated by the same formula, but each with its own specific Rydberg constant, for example:

deuterium Rydberg constant, RD = 1.09707417 × 107
helium-4 Rydberg constant, R4He = 1.09722267 × 107

The series names are sometimes used for these as well, e.g., deuterium Lyman series, HE-II Lyman series, deuterium Balmer series, HE-II Balmer series, etc.


(Lyman,hydrogen,line series,lines,spectrum)
Further reading:
https://en.wikipedia.org/wiki/Lyman_series
https://en.wikipedia.org/wiki/Lyman_limit
https://en.wikipedia.org/wiki/Lyman_continuum_photons
https://en.wikipedia.org/wiki/Hydrogen_spectral_series
http://dept.harpercollege.edu/chemistry/chm/100/dgodambe/thedisk/spec/5back5.htm
http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/hydspec.html
https://www.nist.gov/system/files/documents/srd/jpcrd382009565p.pdf
WaveLFreqPhoton
Energy
  
91.18nm3.3PHz14eVbeginLyman series
121.6nm2.5PHz10eVendLyman series

Referenced by pages:
atomic excitation
Balmer jump (BJ)
Balmer series (H)
Balmer-break galaxy (BBG)
Bohr model
Brackett series
Humphreys series
hydrogen (H)
Lyman alpha (Ly-α)
Lyman beta (Ly-β)
Lyman break (LB)
Lyman continuum (LyC)
Lyman-alpha emitter (LAE)
Lyman-alpha forest
Lyman-break galaxy (LBG)
Paschen series
Pfund series
proximity effect
spectral line
spectral line designation
X-SHOOTER Lyman α survey at z = 2 (XLS-z2)

Index