In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes; the same amount of work is done by the body when decelerating from its current speed to a state of rest. In classical mechanics, the kinetic energy of a non-rotating object of mass m traveling at a speed v is 1 2 m v 2. In relativistic mechanics, this is a good approximation only when v is much less than the speed of light; the standard unit of kinetic energy is the joule. The imperial unit of kinetic energy is the foot-pound; the adjective kinetic has its roots in the Greek word κίνησις kinesis, meaning "motion". The dichotomy between kinetic energy and potential energy can be traced back to Aristotle's concepts of actuality and potentiality; the principle in classical mechanics that E ∝ mv2 was first developed by Gottfried Leibniz and Johann Bernoulli, who described kinetic energy as the living force, vis viva.
Willem's Gravesande of the Netherlands provided experimental evidence of this relationship. By dropping weights from different heights into a block of clay, Willem's Gravesande determined that their penetration depth was proportional to the square of their impact speed. Émilie du Châtelet published an explanation. The terms kinetic energy and work in their present scientific meanings date back to the mid-19th century. Early understandings of these ideas can be attributed to Gaspard-Gustave Coriolis, who in 1829 published the paper titled Du Calcul de l'Effet des Machines outlining the mathematics of kinetic energy. William Thomson Lord Kelvin, is given the credit for coining the term "kinetic energy" c. 1849–51. Energy occurs in many forms, including chemical energy, thermal energy, electromagnetic radiation, gravitational energy, electric energy, elastic energy, nuclear energy, rest energy; these can be categorized in two main classes: kinetic energy. Kinetic energy is the movement energy of an object.
Kinetic energy can be transformed into other kinds of energy. Kinetic energy may be best understood by examples that demonstrate how it is transformed to and from other forms of energy. For example, a cyclist uses chemical energy provided by food to accelerate a bicycle to a chosen speed. On a level surface, this speed can be maintained without further work, except to overcome air resistance and friction; the chemical energy has been converted into kinetic energy, the energy of motion, but the process is not efficient and produces heat within the cyclist. The kinetic energy in the moving cyclist and the bicycle can be converted to other forms. For example, the cyclist could encounter a hill just high enough to coast up, so that the bicycle comes to a complete halt at the top; the kinetic energy has now been converted to gravitational potential energy that can be released by freewheeling down the other side of the hill. Since the bicycle lost some of its energy to friction, it never regains all of its speed without additional pedaling.
The energy is not destroyed. Alternatively, the cyclist could connect a dynamo to one of the wheels and generate some electrical energy on the descent; the bicycle would be traveling slower at the bottom of the hill than without the generator because some of the energy has been diverted into electrical energy. Another possibility would be for the cyclist to apply the brakes, in which case the kinetic energy would be dissipated through friction as heat. Like any physical quantity, a function of velocity, the kinetic energy of an object depends on the relationship between the object and the observer's frame of reference. Thus, the kinetic energy of an object is not invariant. Spacecraft use chemical energy to launch and gain considerable kinetic energy to reach orbital velocity. In an circular orbit, this kinetic energy remains constant because there is no friction in near-earth space. However, it becomes apparent at re-entry. If the orbit is elliptical or hyperbolic throughout the orbit kinetic and potential energy are exchanged.
Without loss or gain, the sum of the kinetic and potential energy remains constant. Kinetic energy can be passed from one object to another. In the game of billiards, the player imposes kinetic energy on the cue ball by striking it with the cue stick. If the cue ball collides with another ball, it slows down and the ball it hit accelerates its speed as the kinetic energy is passed on to it. Collisions in billiards are elastic collisions, in which kinetic energy is preserved. In inelastic collisions, kinetic energy is dissipated in various forms of energy, such as heat, binding energy. Flywheels have been developed as a method of energy storage; this illustrates that kinetic energy is stored in rotational motion. Several mathematical descriptions of kinetic energy exist that describe it in the appropriate physical situation. For objects and processes in common human experience, the formula ½mv² given by Newtonian mechanics is suitable. However, if the speed of the object is comparabl
Pierre Victor Auger
Pierre Victor Auger was a French physicist, born in Paris. He worked in the fields of atomic physics, nuclear physics, cosmic ray physics, he is famous for being one of the discoverers of the Auger effect, named after him. Pierre's father was chemistry professor Victor Auger. Pierre Auger was a student at the École normale supérieure in Paris from 1919 to 1922, the year when he passed the agrégation of physics, he joined the physical chemistry laboratory of the faculté des sciences of the University of Paris under the direction of Jean Perrin to work there on the photoelectric effect. In 1926 he obtained his doctorate in physics from the University of Paris. In 1927, he was named assistant to the faculté des sciences of Paris and, at the same time, adjoint chief of service to l'Institut de biologie physico-chimique. Chief of work to faculty in 1934 and general secretary of the annual tables of the constants in 1936, he was named university lecturer in physics to the faculty on the first of November 1937.
He was charged with, until 1940, the course on the experimental bases of the quantum theory within the chair of theoretical physics and astrophysics. He was adjoint director of the laboratory of physical chemistry, he occupied the chair of quantum physics and relativity of the faculté des sciences of Paris. At the end of World War II, he was named director of higher education from 1945 to 1948, which permitted him to introduce the first chair of genetics at the Sorbonne, conferred upon Boris Ephrussi; the process where Auger electrons are emitted from atoms is used in Auger electron spectroscopy to study the elements on the surface of materials. This method was named after him, despite the fact that Lise Meitner discovered the process a few years before in 1922. In his work with cosmic rays, he found that the cosmic radiation events were coincident in time meaning that they were associated with a single event, an air shower, he estimated that the energy of the incoming particle that creates large air showers must be at least 1015 electronvolts = 106 particles of 108 eV and a factor of ten for energy loss from traversing the atmosphere.
He was European Space Research Organisation first Director General and one of the forefathers for the CERN foundation. He was president of the Centre international de calcul. From 1948 to 1959, he directed at UNESCO the department of natural sciences, he was elected a member of the Académie des sciences in 1977. He hosted a broadcast of popularization of exacting science on Friday evenings on the public radio station France Culture from September 1969 to June 1986, entitled Les Grandes Avenues de la science moderne; the world's largest cosmic ray detector, the Pierre Auger Observatory, is named after him. Auger therapy Pierre Auger: The Pioneering Work Entretien du 23 avril 1986 avec Pierre Auger
In physics and electronic engineering, an electron hole is the lack of an electron at a position where one could exist in an atom or atomic lattice. Since in a normal atom or crystal lattice the negative charge of the electrons is balanced by the positive charge of the atomic nuclei, the absence of an electron leaves a net positive charge at the hole's location. Holes are not particles, but rather quasiparticles. Holes in a metal or semiconductor crystal lattice can move through the lattice as electrons can, act to positively-charged particles, they play an important role in the operation of semiconductor devices such as transistors and integrated circuits. If an electron is excited into a higher state it leaves a hole in its old state; this meaning is used in Auger electron spectroscopy, in computational chemistry, to explain the low electron-electron scattering-rate in crystals. In crystals, electronic band structure calculations lead to an effective mass for the electrons, negative at the top of a band.
The negative mass is an unintuitive concept, in these situations a more familiar picture is found by considering a positive charge with a positive mass. In solid-state physics, an electron hole is the absence of an electron from a full valence band. A hole is a way to conceptualize the interactions of the electrons within a nearly full valence band of a crystal lattice, missing a small fraction of its electrons. In some ways, the behavior of a hole within a semiconductor crystal lattice is comparable to that of the bubble in a full bottle of water. Hole conduction in a valence band can be explained by the following analogy. Imagine a row of people seated in an auditorium, where there are no spare chairs. Someone in the middle of the row wants to leave, so he jumps over the back of the seat into another row, walks out; the empty row is analogous to the conduction band, the person walking out is analogous to a conduction electron. Now imagine someone else comes along and wants to sit down; the empty row has a poor view.
Instead, a person in the crowded row moves into the empty seat the first person left behind. The empty seat moves one spot closer to the person waiting to sit down; the next person follows, the next, et cetera. One could say. Once the empty seat reaches the edge, the new person can sit down. In the process everyone in the row has moved along. If those people were negatively charged, this movement would constitute conduction. If the seats themselves were positively charged only the vacant seat would be positive; this is a simple model of how hole conduction works. Instead of analyzing the movement of an empty state in the valence band as the movement of many separate electrons, a single equivalent imaginary particle called a "hole" is considered. In an applied electric field, the electrons move in one direction, corresponding to the hole moving in the other. If a hole associates itself with a neutral atom, that atom becomes positive. Therefore, the hole is taken to have positive charge of +e the opposite of the electron charge.
In reality, due to the uncertainty principle of quantum mechanics, combined with the energy levels available in the crystal, the hole is not localizable to a single position as described in the previous example. Rather, the positive charge which represents the hole spans an area in the crystal lattice covering many hundreds of unit cells; this is equivalent to being unable to tell. Conduction band electrons are delocalized; the analogy above is quite simplified, cannot explain why holes create an opposite effect to electrons in the Hall effect and Seebeck effect. A more precise and detailed explanation follows; the dispersion relation determines. A dispersion relation is the relationship between wavevector and energy in a band, part of the electronic band structure. In quantum mechanics, the electrons are waves, energy is the wave frequency. A localized electron is a wavepacket, the motion of an electron is given by the formula for the group velocity of a wave. An electric field affects an electron by shifting all the wavevectors in the wavepacket, the electron accelerates when its wave group velocity changes.
Therefore, the way an electron responds to forces is determined by its dispersion relation. An electron floating in space has the dispersion relation E=ℏ2k2/, where m is the electron mass and ℏ is reduced Planck constant. Near the bottom of the conduction band of a semiconductor, the dispersion relation is instead E=ℏ2k2/, so a conduction-band electron responds to forces as if it had the mass m*. Electrons near the top of the valence band behave; the dispersion relation near the top of the valence band is E=ℏ2k2/ with negative effective mass. So electrons near the top of the valence band behave; when a force pulls the electrons to the right, these electrons move left. This is due to the shape of the valence band, is unrelated to whether the band is full or empty. If you could somehow empty out the valence band and just put one electron near the valence band maximum, this electron would move the "wrong way" in response to forces. Po
In chemistry and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus. The closest shell to the nucleus is called the "1 shell", followed by the "2 shell" the "3 shell", so on farther and farther from the nucleus; the shells correspond with the principal quantum numbers or are labeled alphabetically with letters used in the X-ray notation. Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight electrons, the third shell can hold up to 18 and so on; the general formula is. Since electrons are electrically attracted to the nucleus, an atom's electrons will occupy outer shells only if the more inner shells have been filled by other electrons. However, this is not a strict requirement: atoms may have two or three incomplete outer shells. For an explanation of why electrons exist in these shells see electron configuration; the electrons in the outermost occupied shell determine the chemical properties of the atom.
Each shell consists of one or more subshells, each subshell consists of one or more atomic orbitals. The shell terminology comes from Arnold Sommerfeld's modification of the Bohr model. Sommerfeld retained Bohr's planetary model, but added mildly elliptical orbits to explain the fine spectroscopic structure of some elements; the multiple electrons with the same principal quantum number had close orbits that formed a "shell" of positive thickness instead of the infinitely thin circular orbit of Bohr's model. The existence of electron shells was first observed experimentally in Charles Barkla's and Henry Moseley's X-ray absorption studies. Barkla labeled them with the letters K, L, M, N, O, P, Q; the origin of this terminology was alphabetic. A "J" series was suspected, though experiments indicated that the K absorption lines are produced by the innermost electrons; these letters were found to correspond to the n values 1, 2, 3, etc. They are used in the spectroscopic Siegbahn notation; the physical chemist Gilbert Lewis was responsible for much of the early development of the theory of the participation of valence shell electrons in chemical bonding.
Linus Pauling generalized and extended the theory while applying insights from quantum mechanics. The electron shells are labeled K, L, M, N, O, P, Q. Electrons in outer shells have higher average energy and travel farther from the nucleus than those in inner shells; this makes them more important in determining how the atom reacts chemically and behaves as a conductor, because the pull of the atom's nucleus upon them is weaker and more broken. In this way, a given element's reactivity is dependent upon its electronic configuration; each shell is composed of one or more subshells. For example, the first shell has one subshell, called 1s; the various possible subshells are shown in the following table: The first column is the "subshell label", a lowercase-letter label for the type of subshell. For example, the "4s subshell" is a subshell of the fourth shell, with the type described in the first row; the second column is the azimuthal quantum number of the subshell. The precise definition involves quantum mechanics, but it is a number that characterizes the subshell.
The third column is the maximum number of electrons. For example, the top row says. In each case the figure is 4 greater than the one above it; the fourth column says. For example, looking at the top two rows, every shell has an s subshell, while only the second shell and higher have a p subshell; the final column gives the historical origin of the labels s, p, d, f. They come from early studies of atomic spectral lines; the other labels, namely g, h and i, are an alphabetic continuation following the last originated label of f. Although it is stated that all the electrons in a shell have the same energy, this is an approximation. However, the electrons in one subshell do have the same level of energy, with subshells having more energy per electron than earlier ones; this effect is great enough. Each subshell is constrained to hold 4ℓ + 2 electrons at most, namely: Each s subshell holds at most 2 electrons Each p subshell holds at most 6 electrons Each d subshell holds at most 10 electrons Each f subshell holds at most 14 electrons Each g subshell holds at most 18 electronsTherefore, the K shell, which contains only an s subshell, can hold up to 2 electrons.
Although that formula gives the maximum in principle, in fact that maximum is only achieved for the first four shells (K, L, M
The electron is a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, are thought to be elementary particles because they have no known components or substructure; the electron has a mass, 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum of a half-integer value, expressed in units of the reduced Planck constant, ħ; as it is a fermion, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be diffracted like light; the wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy. Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism and thermal conductivity, they participate in gravitational and weak interactions.
Since an electron has charge, it has a surrounding electric field, if that electron is moving relative to an observer, it will generate a magnetic field. Electromagnetic fields produced from other sources will affect the motion of an electron according to the Lorentz force law. Electrons absorb energy in the form of photons when they are accelerated. Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as electronics, cathode ray tubes, electron microscopes, radiation therapy, gaseous ionization detectors and particle accelerators. Interactions involving electrons with other subatomic particles are of interest in fields such as chemistry and nuclear physics; the Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without, allows the composition of the two known as atoms.
Ionization or differences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding. In 1838, British natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Irish physicist George Johnstone Stoney named this charge'electron' in 1891, J. J. Thomson and his team of British physicists identified it as a particle in 1897. Electrons can participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere; the antiparticle of the electron is called the positron. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.
The ancient Greeks noticed. Along with lightning, this phenomenon is one of humanity's earliest recorded experiences with electricity. In his 1600 treatise De Magnete, the English scientist William Gilbert coined the New Latin term electrica, to refer to those substances with property similar to that of amber which attract small objects after being rubbed. Both electric and electricity are derived from the Latin ēlectrum, which came from the Greek word for amber, ἤλεκτρον. In the early 1700s, Francis Hauksbee and French chemist Charles François du Fay independently discovered what they believed were two kinds of frictional electricity—one generated from rubbing glass, the other from rubbing resin. From this, du Fay theorized that electricity consists of two electrical fluids and resinous, that are separated by friction, that neutralize each other when combined. American scientist Ebenezer Kinnersley also independently reached the same conclusion. A decade Benjamin Franklin proposed that electricity was not from different types of electrical fluid, but a single electrical fluid showing an excess or deficit.
He gave them the modern charge nomenclature of negative respectively. Franklin thought of the charge carrier as being positive, but he did not identify which situation was a surplus of the charge carrier, which situation was a deficit. Between 1838 and 1851, British natural philosopher Richard Laming developed the idea that an atom is composed of a core of matter surrounded by subatomic particles that had unit electric charges. Beginning in 1846, German physicist William Weber theorized that electricity was composed of positively and negatively charged fluids, their interaction was governed by the inverse square law. After studying the phenomenon of electrolysis in 1874, Irish physicist George Johnstone Stoney suggested that there existed a "single definite quantity of electricity", the charge of a monovalent ion, he was able to estimate the value of this elementary charge e by means of Faraday's laws of electrolysis. However, Stoney could not be removed. In 1881, German physicist Hermann von Helmholtz argued that both positive and negative charges were divided into elementary parts, each of which "behaves like atoms of electricity".
Stoney coined the term
In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the SI unit of energy is the joule, the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton. Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field, the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, the thermal energy due to an object's temperature. Mass and energy are related. Due to mass–energy equivalence, any object that has mass when stationary has an equivalent amount of energy whose form is called rest energy, any additional energy acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale.
Living organisms require exergy to stay alive, such as the energy. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy; the processes of Earth's climate and ecosystem are driven by the radiant energy Earth receives from the sun and the geothermal energy contained within the earth. The total energy of a system can be subdivided and classified into potential energy, kinetic energy, or combinations of the two in various ways. Kinetic energy is determined by the movement of an object – or the composite motion of the components of an object – and potential energy reflects the potential of an object to have motion, is a function of the position of an object within a field or may be stored in the field itself. While these two categories are sufficient to describe all forms of energy, it is convenient to refer to particular combinations of potential and kinetic energy as its own form. For example, macroscopic mechanical energy is the sum of translational and rotational kinetic and potential energy in a system neglects the kinetic energy due to temperature, nuclear energy which combines utilize potentials from the nuclear force and the weak force), among others.
The word energy derives from the Ancient Greek: translit. Energeia, lit.'activity, operation', which appears for the first time in the work of Aristotle in the 4th century BC. In contrast to the modern definition, energeia was a qualitative philosophical concept, broad enough to include ideas such as happiness and pleasure. In the late 17th century, Gottfried Leibniz proposed the idea of the Latin: vis viva, or living force, which defined as the product of the mass of an object and its velocity squared. To account for slowing due to friction, Leibniz theorized that thermal energy consisted of the random motion of the constituent parts of matter, although it would be more than a century until this was accepted; the modern analog of this property, kinetic energy, differs from vis viva only by a factor of two. In 1807, Thomas Young was the first to use the term "energy" instead of vis viva, in its modern sense. Gustave-Gaspard Coriolis described "kinetic energy" in 1829 in its modern sense, in 1853, William Rankine coined the term "potential energy".
The law of conservation of energy was first postulated in the early 19th century, applies to any isolated system. It was argued for some years whether heat was a physical substance, dubbed the caloric, or a physical quantity, such as momentum. In 1845 James Prescott Joule discovered the generation of heat; these developments led to the theory of conservation of energy, formalized by William Thomson as the field of thermodynamics. Thermodynamics aided the rapid development of explanations of chemical processes by Rudolf Clausius, Josiah Willard Gibbs, Walther Nernst, it led to a mathematical formulation of the concept of entropy by Clausius and to the introduction of laws of radiant energy by Jožef Stefan. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time. Thus, since 1918, theorists have understood that the law of conservation of energy is the direct mathematical consequence of the translational symmetry of the quantity conjugate to energy, namely time.
In 1843, James Prescott Joule independently discovered the mechanical equivalent in a series of experiments. The most famous of them used the "Joule apparatus": a descending weight, attached to a string, caused rotation of a paddle immersed in water insulated from heat transfer, it showed that the gravitational potential energy lost by the weight in descending was equal to the internal energy gained by the water through friction with the paddle. In the International System of Units, the unit of energy is the joule, named after James Prescott Joule, it is a derived unit. It is equal to the energy expended in applying a force of one newton through a distance of one metre; however energy is expressed in many other units not part of the SI, such as ergs, British Thermal Units, kilowatt-hours and kilocalories, which require a conversion factor when expressed in SI units. The SI unit of energy rate is the watt, a joule per second. Thus, one joule is one watt-second, 3600 joules equal one wa
Auger electron spectroscopy
Auger electron spectroscopy is a common analytical technique used in the study of surfaces and, more in the area of materials science. Underlying the spectroscopic technique is the Auger effect, as it has come to be called, based on the analysis of energetic electrons emitted from an excited atom after a series of internal relaxation events; the Auger effect was discovered independently by both Lise Pierre Auger in the 1920s. Though the discovery was made by Meitner and reported in the journal Zeitschrift für Physik in 1922, Auger is credited with the discovery in most of the scientific community; until the early 1950s Auger transitions were considered nuisance effects by spectroscopists, not containing much relevant material information, but studied so as to explain anomalies in X-ray spectroscopy data. Since 1953 however, AES has become a practical and straightforward characterization technique for probing chemical and compositional surface environments and has found applications in metallurgy, gas-phase chemistry, throughout the microelectronics industry.
The Auger effect is an electronic process at the heart of AES resulting from the inter- and intrastate transitions of electrons in an excited atom. When an atom is probed by an external mechanism, such as a photon or a beam of electrons with energies in the range of several eV to 50 keV, a core state electron can be removed leaving behind a hole; as this is an unstable state, the core hole can be filled by an outer shell electron, whereby the electron moving to the lower energy level loses an amount of energy equal to the difference in orbital energies. The transition energy can be coupled to a second outer shell electron, which will be emitted from the atom if the transferred energy is greater than the orbital binding energy. An emitted electron will have a kinetic energy of: E kin = E Core State − E B − E C ′ where E Core State, E B, E C ′ are the core level, first outer shell, second outer shell electron binding energies which are taken to be positive; the apostrophe denotes a slight modification to the binding energy of the outer shell electrons due to the ionized nature of the atom.
Since orbital energies are unique to an atom of a specific element, analysis of the ejected electrons can yield information about the chemical composition of a surface. Figure 1 illustrates two schematic views of the Auger process; the types of state-to-state transitions available to electrons during an Auger event are dependent on several factors, ranging from initial excitation energy to relative interaction rates, yet are dominated by a few characteristic transitions. Because of the interaction between an electron's spin and orbital angular momentum and the concomitant energy level splitting for various shells in an atom, there are a variety of transition pathways for filling a core hole. Energy levels are labeled using a number of different schemes such as the j-j coupling method for heavy elements, the Russell-Saunders L-S method for lighter elements, a combination of both for intermediate elements; the j-j coupling method, linked to X-ray notation, is always used to denote Auger transitions.
Thus for a K L 1 L 2, 3 transition, K represents the core level hole, L 1 the relaxing electron's initial state, L 2, 3 the emitted electron's initial energy state. Figure 1 illustrates this transition with the corresponding spectroscopic notation; the energy level of the core hole will determine which transition types will be favored. For single energy levels, i.e. K, transitions can occur from the L levels, giving rise to strong KLL type peaks in an Auger spectrum. Higher level transitions can occur, but are less probable. For multi-level shells, transitions are available from higher energy orbitals or energy levels within the same shell; the result are transitions of the type LMM and KLL along with faster Coster–Kronig transitions such as LLM. While Coster–Kronig transitions are faster, they are less energetic and thus harder to locate on an Auger spectrum; as the atomic number Z increases, so too does the number of potential Auger transitions. The strongest electron-electron interactions are between levels that are close together, giving rise to characteristic peaks in an Auger spectrum.
KLL and LMM peaks are some of the most identified transitions during surface analysis. Valence band electrons can fill core holes or be emitted during KVV-type transitions. Several models, both phenomenological and analytical, have been developed to describe the energetics of Auger transitions. One of the most tractable descriptions, put forth by Jenkins and Chung, estimates the energy of Auger transition ABC as: E A B C = E A − 0.5 [ E B (