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An electron and electron hole ( electron-hole pair ) can recombine giving up their energy to an electron in the conduction band, increasing its energy.
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electron and hole
But, when lifted out, it would leave behind a hole in the sea that would act exactly like a positive-energy electron with a reversed charge.
An incident electron ( or photon ) creates a core hole in the 1s level.
An electron from the 2s level fills in the 1s hole and the transition energy is imparted to a 2p electron which is emitted.
If the carriers are holes, replace electron density by the negative of the hole density.
For more massive stars, electron degeneracy pressure will not keep the iron core from collapsing to very great density, leading to formation of a neutron star, black hole, or, speculatively, a quark star.
In the classical view, there are only electrons moving in the same average direction both in the case of electron or hole conductivity.
A hole can be created for a p-type dopant, and an electron for an n-type dopant.
When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon.
* Black hole electron
The holes themselves don't move, but a neighboring electron can move to fill the hole, leaving a hole at the place it has just come from, and in this way the holes appear to move, and the holes behave as if they were actual positively charged particles.
Sometimes even in this case it may be said that a hole was left behind, to explain why the electron does not fall back to lower energies: It cannot find a hole.
The effective mass is important as it affects many of the electrical properties of the semiconductor, such as the electron or hole mobility, which in turn influences the diffusivity of the charge carriers and the electrical conductivity of the semiconductor.
When ionizing radiation strikes a semiconductor, it may excite an electron out of its energy level and consequently leave a hole.
This process is known as electron – hole pair generation.
In some states, the generation and recombination of electron – hole pairs are in equipoise.
The probability of meeting is increased by carrier traps — impurities or dislocations which can trap an electron or hole and hold it until a pair is completed.
where n < sub > 0 </ sub > is the concentration of conducting electrons, p < sub > 0 </ sub > is the electron hole concentration, and n < sub > i </ sub > is the material's intrinsic carrier concentration.
If the mass of the core exceeds the Chandrasekhar limit, electron degeneracy pressure will be unable to support its weight against the force of gravity, and the core will undergo sudden, catastrophic collapse to form a neutron star or ( in the case of cores that exceed the Tolman-Oppenheimer-Volkoff limit ), a black hole.
When an atom is probed by an external mechanism, such as a photon or a beam of electrons with energies in the range of 2 keV to 50 keV, a core state electron can be removed leaving behind a hole.
electron and electron-hole
In a direct bandgap material, recombination of these electron-hole pairs will result in cathodoluminescence ; if the sample contains an internal electric field, such as is present at a p-n junction, the SEM beam injection of carriers will cause electron beam induced current ( EBIC ) to flow.
An electron is said to be found in the lowest unoccupied orbital and an electron hole in the highest occupied molecular orbital, and since they are found within the same molecular orbital manifold, the electron-hole state is said to be bound.
* Y < sub > 2 </ sub > O < sub > 3 </ sub >: Eu phosphors under electron bombardment in presence of oxygen form a non-phosphorescent layer on the surface, where electron-hole pairs recombine nonradiatively via surface states.
Another dating method using electron spin resonance ( ESR ) — also known as electron paramagnetic resonance ( EPR ) — is based on the measurement of electron-hole centers accumulated with time in the crystal lattice of CaCO < sub > 3 </ sub > exposed to natural radiations.
In a simplified model of the excitation, the energy of the emitted photon can be seen as a sum of the band gap energy between occupied level and unoccupied energy level, the confinement energies of the hole and the excited electron, and the bound energy of the exciton ( the electron-hole pair ):
The generated electron concentration does not follow the electric field instantaneously because it also depends on the number of electron-hole pairs already present in the avalanche region.
electron and pair
A Lewis acid is a species that accepts a pair of electrons from another species ; in other words, it is an electron pair acceptor.
Brønsted acid-base reactions are proton transfer reactions while Lewis acid-base reactions are electron pair transfers.
In the first reaction a fluoride ion, F < sup >−</ sup >, gives up an electron pair to boron trifluoride to form the product tetrafluoroborate.
BF < sub > 3 </ sub > is a Lewis acid because it accepts the electron pair from fluoride.
The species that gains the electron pair is the Lewis acid ; for example, the oxygen atom in H < sub > 3 </ sub > O < sup >+</ sup > gains a pair of electrons when one of the H — O bonds is broken and the electrons shared in the bond become localized on oxygen.
An atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom.
As predicted by the VSEPR model of electron pair repulsion, the molecular geometry of alkenes includes bond angles about each carbon in a double bond of about 120 °.
The acetylide conjugate base is stabilized as a result of the high s character of the sp orbital, in which the electron pair resides.
The copper is removed by bonding to a ligand, which is a large molecule consisting of a number of smaller groups, each possessing a lone electron pair.
In this " condensed " state, the breaking of one pair will change the energy of the entire condensate-not just a single electron, or a single pair.
The electron pair from the nucleophile attacks the substrate forming a new bond, while the leaving group departs with an electron pair.
Ligands are generally bound to the central atom by a coordinate covalent bond ( donating electrons from a lone electron pair into an empty metal orbital ), and are said to be coordinated to the atom.
In the free electron laser ( FEL ), a relativistic electron beam is passed through a pair of undulators containing arrays of dipole magnets, whose fields are oriented in alternating directions.
* Polyhedral skeletal electron pair theory for cluster compounds, including transition metals and main group elements such as boron including Wade's rules for polyhedral cluster compounds, including transition metals and main group elements and mixtures thereof.
The Hilbert space of the electron pair is, the tensor product of the two electrons ' Hilbert spaces.
electron and can
Hence, the electron paramagnetic effects ( slope ) can be separated from the nuclear effects ( intercept ).
Protons have a positive charge and a mass 1, 836 times that of the electron, at, although this can be reduced by changes to the energy binding the proton into an atom.
This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus.
The term may also refer to the physical region where the electron can be calculated to be, as defined by the particular mathematical form of the orbital.
The lowest possible energy an electron can take is therefore analogous to the fundamental frequency of a wave on a string.
# The electrons are never in a single point location, although the probability of interacting with the electron at a single point can be found from the wave function of the electron.
For example, one can say for a given transition that it corresponds to the excitation of an electron from an occupied orbital to a given unoccupied orbital.
Atomic orbitals can be the hydrogen-like " orbitals " which are exact solutions to the Schrödinger equation for a hydrogen-like " atom " ( i. e., an atom with one electron ).
For example, a positron ( the antiparticle of the electron, with symbol ) and an antiproton ( symbol ) can form an antihydrogen atom.
Although sometimes this energy is released in the form of an emitted photon, the energy can also be transferred to another electron, which is ejected from the atom.
Microscopy can be categorized into three different fields: optical microscopy, electron microscopy, and scanning probe microscopy.
This unstable intermediate can lead to electron " leakage ", when electrons jump directly to oxygen and form the superoxide anion, instead of moving through the normal series of well-controlled reactions of the electron transport chain.
However, although these enzymes can produce oxidants, the relative importance of the electron transfer chain to other processes that generate peroxide is unclear.
This means there is an energy gap for single-particle excitation, unlike in the normal metal ( where the state of an electron can be changed by adding an arbitrarily small amount of energy ).
Such particles are normally invisible in an optical microscope, though their presence can be confirmed with the use of an ultramicroscope or an electron microscope.
Neutrons can also probe atomic length scales and are used to study scattering off nuclei and electron spins and magnetization ( as neutrons themselves have spin but no charge ).
Coulomb and Mott scattering measurements can be made by using electron beams as scattering probes, and similarly, positron annihilation can be used as an indirect measurement of local electron density.
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