Lyman limit
Encyclopedia
The Lyman limit is the short-wavelength end of the Hydrogen
Lyman series
, at 91.2 nm. It corresponds to the energy required for an electron
in the Hydrogen ground state to escape from the electric potential
barrier that originally confined it, thus creating a Hydrogen ion
. This energy is equivalent to the Rydberg constant
.
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
Lyman series
Lyman series
In physics and chemistry, the Lyman series is the series of transitions and resulting ultraviolet emission lines of the hydrogen atom as an electron goes from n ≥ 2 to n = 1...
, at 91.2 nm. It corresponds to the energy required for an electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
in the Hydrogen ground state to escape from the electric potential
Electric potential
In classical electromagnetism, the electric potential at a point within a defined space is equal to the electric potential energy at that location divided by the charge there...
barrier that originally confined it, thus creating a Hydrogen ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
. This energy is equivalent to the Rydberg constant
Rydberg constant
The Rydberg constant, symbol R∞, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to atomic spectra in the science of spectroscopy. Rydberg initially determined its value empirically from spectroscopy, but Niels Bohr later showed that its value could be calculated...
.
See also
- Lyman alpha emitterLyman alpha emitterLyman alpha emitters are a type of distant galaxy that emits Lyman-alpha radiation. They are extremely distant and because of the finite travel time of light they are glimpses of the past history of the universe. They are thought to be the progenitors of most modern Milky Way type galaxies...
- Lyman-alpha forestLyman-alpha forestIn astronomical spectroscopy, the Lyman-alpha forest is the sum of absorption lines arising from the Lyman-alpha transition of the neutral hydrogen in the spectra of distant galaxies and quasars....
- Lyman-break galaxyLyman-break galaxyLyman-break galaxies are star-forming galaxies at high redshift that are selected using the differing appearance of the galaxy in several imaging filters due to the position of the Lyman limit...
- Rydberg formulaRydberg formulaThe Rydberg formula is used in atomic physics to describe the wavelengths of spectral lines of many chemical elements. It was formulated by the Swedish physicist Johannes Rydberg, and presented on November 5, 1888.-History:...