Fr.: capture d'électron
A process whereby an → unstable atom becomes stable. In this process, an → electron in an atom's inner shell is drawn into the → nucleus where it combines with a → proton, forming a → neutron and a → neutrino. The neutrino escapes from the atom's nucleus. The result is an element change, because the atom loses a proton. For example, an atom of → carbon (with 6 protons) becomes an atom of → boron (with 5 protons). Electron capture is also called K-capture since the captured electron usually comes from the atom's K-shell. See also → neutronization.
bâr-e elektron (#)
Fr.: charge de l'électron
Fr.: configuration électronique
Of an atom, a form of notation which shows how the electrons are distributed among the various atomic orbital and energy levels. The format consists of a series of numbers, letters and superscripts. For example, 1s2 2s2 2p3 means: 2 electrons in the 1s subshell, 2 electrons in the 2s subshell, and 3 electrons in the 2p subshell.
vâgeni-ye elektron (#)
Fr.: dégénérescence des électrons
A → degenerate matter in which electrons are very tightly packed together, as in a white dwarf, but cannot get closer than a certain limit to each other, because according to quantum mechanics laws (→ Pauli exclusion principle) the lowest energy levels can be occupied by only one electron. Therefore, electrons are forced into high energy states. And the significant pressure created by these high energy electrons supports white dwarf stars against their own gravity.
cagâli-ye elektroni (#)
Fr.: densité électronique
parâš-e elekroni (#)
Fr.: diffraction des électrons
A diffraction phenomenon resulting from the passage of electrons through matter, analogous to the diffraction of visible light. This phenomenon is the main evidence for the existence of waves associated with elementary particles; → de Broglie wavelength.
jerm-e elekron (#)
Fr.: masse de l'électron
The mass of an electron, which is 9.109 382 91 × 10-28 g.
Fr.: rayon de l'électron
puste-ye elekroni (#)
Fr.: couche éléctronique
Any of up to seven energy levels on which an electron may exist within an atom, the energies of the electrons on the same level being equal and on different levels being unequal. The number of electrons permitted in a shell is equal to 2n2. A shell contains n2 orbitals, and n subshells.
damâ-ye elektroni (#)
Fr.: température électronique
1) The temperature of electrons in an interstellar ionized nebula (e.g. in
→ H II regions and
→ planetary nebulae) as determined by characteristic
→ emission lines (optical
→ forbidden lines or
→ radio recombination lines).
electron volt (eV)
joft-e elektron-pozitron (#)
Fr.: paire électron-positron
bâl-e parâkaneš-e elektron
A → line broadening phenomenon involving the scattering effect of → free electrons on the → radiation transfer in → stellar atmospheres. The scattering of radiation by free electrons plays an important role in the atmospheres of → hot stars, such as → O-types, early → B-types, and → Wolf-Rayet stars. The first detailed study of electron scattering in Wolf-Rayet stars was by Castor et al. (1970), who used electron scattering to explain the broad emission wings of N IV λ3483 in HD 192163. In → P Cygni stars the explanation of the very extended (almost symmetric) wings on the → Balmer lines as caused by electron scattering was first made by Bernat & Lambert (1978). Hillier (1991) showed that significant reduction in the strength of an electron-scattering wing can be achieved in a model of → clumped wind for a lower mean → mass loss rate. This resulted in a better agreement between observations and theoretical predictions. Electron-scattering wings provide diagnostics regarding the presence of density inhomogeneities in → stellar winds (Münch, 1948, ApJ 108, 116; Hillier, 1991, A&A 247, 455).
Fr.: état éléctronique
In molecular quantum mechanics, any of → quantum states corresponding to a particular → electron configuration (i.e. an arrangement of the electron(s) in certain → orbitals). The electron configuration with the lowest energy is called the → ground state. All higher energy states are called → excited states.
An instrument for detecting electric charges or → potential differences.
Referring to electric charges at rest.
Fr.: charge électrostatique
A quantity of electricity at rest on the surface of an insulator or an insulated conductor.
meydân-e barqistâ (#)
Fr.: champ électrostatique
A region of space in which a non-moving → electric charge would be subjected to a force of attraction or repulsion as a result of the presence of another stationary electric charge. The electrostatic field is a special case of the → electromagnetic field.
Fr.: induction électrostatique
The production of stationary electric charges on an uncharged object as a result of a charged body being brought near it without touching it. A positive charge will induce a negative charge, and vice versa.