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Above-threshold Ionization
In atomic, molecular, and optical physics, above-threshold ionization (ATI) is a multi-photon effect where an atom is ionized with more than the energetically required number of photons. It was first observed in 1979 by Pierre Agostini and colleagues in xenon gas. Photoelectrons In the case of ATI the photoelectron peaks should appear at : E_s = (n + s) \hbar \omega - W, where the integer ''n'' represents the minimal number of photons absorbed, and the integer ''s'' represents the number of additional photons absorbed. ''W'' is the ionization energy, and E_s is the electron kinetic energy of the peak corresponding to ''s'' additional photons being absorbed. Structure It typically has a strong maximum at the minimal number of photons to ionize the system, with successive peaks (known as ATI peaks) separated by the photon energy and thus corresponding to higher numbers of photons being absorbed. In the non-perturbative regime the bound states are dressed with the electric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen PES 95eV 1e15
Hydrogen is a chemical element; it has symbol H and atomic number 1. It is the lightest and most abundant chemical element in the universe, constituting about 75% of all normal matter. Under standard conditions, hydrogen is a gas of diatomic molecules with the formula , called dihydrogen, or sometimes hydrogen gas, molecular hydrogen, or simply hydrogen. Dihydrogen is colorless, odorless, non-toxic, and highly combustible. Stars, including the Sun, mainly consist of hydrogen in a plasma state, while on Earth, hydrogen is found as the gas (dihydrogen) and in molecular forms, such as in water and organic compounds. The most common isotope of hydrogen (H) consists of one proton, one electron, and no neutrons. Hydrogen gas was first produced artificially in the 17th century by the reaction of acids with metals. Henry Cavendish, in 1766–1781, identified hydrogen gas as a distinct substance and discovered its property of producing water when burned; hence its name means 'water-f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic, Molecular, And Optical Physics
Atomic, molecular, and optical physics (AMO) is the study of matter–matter and light–matter interactions, at the scale of one or a few atoms and energy scales around several electron volts. The three areas are closely interrelated. AMO theory includes classical, semi-classical and quantum treatments. Typically, the theory and applications of emission, absorption, scattering of electromagnetic radiation (light) from Excited state, excited atoms and molecules, analysis of spectroscopy, generation of lasers and masers, and the optical properties of matter in general, fall into these categories. Atomic and molecular physics Atomic physics is the subfield of AMO that studies atoms as an isolated system of electrons and an atomic nuclei, atomic nucleus, while molecular physics is the study of the physical properties of molecules. The term ''atomic physics'' is often associated with nuclear power and nuclear bombs, due to the synonymous use of ''atomic'' and ''nuclear'' i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectrochemical Processes
Photoelectrochemical processes are processes in photoelectrochemistry; they usually involve transforming light into other forms of energy. These processes apply to photochemistry, optically pumped lasers, sensitized solar cells, luminescence, and photochromism. Electron excitation Electron excitation is the movement of an electron to a higher energy state. This can either be done by photoexcitation (PE), where the original electron absorbs the photon and gains all the photon's energy or by electrical excitation (EE), where the original electron absorbs the energy of another, energetic electron. Within a semiconductor crystal lattice, thermal excitation is a process where lattice vibrations provide enough energy to move electrons to a higher energy band. When an excited electron falls back to a lower energy state again, it is called electron relaxation. This can be done by radiation of a photon or giving the energy to a third spectator particle as well. In physics there is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless particles that can move no faster than the speed of light measured in vacuum. The photon belongs to the class of boson particles. As with other elementary particles, photons are best explained by quantum mechanics and exhibit wave–particle duality, their behavior featuring properties of both waves and particles. The modern photon concept originated during the first two decades of the 20th century with the work of Albert Einstein, who built upon the research of Max Planck. While Planck was trying to explain how matter and electromagnetic radiation could be in thermal equilibrium with one another, he proposed that the energy stored within a material object should be regarded as composed of an integer number of discrete, equal-sized parts. To explain the pho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Agostini
Pierre Agostini (; born 23 July 1941) is a French experimental physicist and Emeritus professor at the Ohio State University in the United States, known for his pioneering work in strong-field laser physics and attosecond science. He is especially known for the observation of above-threshold ionization and the invention of the reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) technique for characterization of attosecond light pulses. He was jointly awarded the 2023 Nobel Prize in Physics. Education and career Pierre Agostini was born in Tunis, in the French protectorate of Tunisia, in 1941. He obtained his ''baccalauréat'' at the Prytanée national militaire school in 1959 in La Flèche, France. Agostini studied physics at Aix-Marseille University, where he subsequently received a B.Ed. degree (''licence d'enseignement'') in physics in 1961, and an M.A.S. degree (''diplôme d'études approfondies'') in 1962. In 1968 he completed a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenon
Xenon is a chemical element; it has symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized. Xenon is used in flash lamps and arc lamps, and as a general anesthetic. The first excimer laser design used a xenon dimer molecule (Xe2) as the lasing medium, and the earliest laser designs used xenon flash lamps as pumps. Xenon is also used to search for hypothetical weakly interacting massive particles and as a propellant for ion thrusters in spacecraft. Naturally occurring xenon consists of seven stable isotopes and two long-lived radioactive isotopes. More than 40 unstable xenon isotopes undergo radioactive decay, and the isotope ratios of xenon are an important tool for studying the early history of the Solar System. Radioactive xe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectron
The photoelectric effect is the emission of electrons from a material caused by electromagnetic radiation such as ultraviolet light. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, solid state, and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission. The experimental results disagree with classical electromagnetism, which predicts that continuous light waves transfer energy to electrons, which would then be emitted when they accumulate enough energy. An alteration in the intensity of light would theoretically change the kinetic energy of the emitted electrons, with sufficiently dim light resulting in a delayed emission. The experimental results instead show that electrons are dislodged only when the light exceeds a certain frequency—regardless of the ligh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionization Energy
In physics and chemistry, ionization energy (IE) is the minimum energy required to remove the most loosely bound electron of an isolated gaseous atom, Ion, positive ion, or molecule. The first ionization energy is quantitatively expressed as :X(g) + energy ⟶ X+(g) + e− where X is any atom or molecule, X+ is the resultant ion when the original atom was stripped of a single electron, and e− is the removed electron. Ionization energy is positive for neutral atoms, meaning that the ionization is an endothermic process. Roughly speaking, the closer the outermost electrons are to the atomic nucleus, nucleus of the atom, the higher the atom's ionization energy. In physics, ionization energy (IE) is usually expressed in electronvolts (eV) or joules (J). In chemistry, it is expressed as the energy to ionize a Mole (unit), mole of atoms or molecules, usually as Joule per mole, kilojoules per mole (kJ/mol) or Kilocalorie per mole, kilocalories per mole (kcal/mol). Comparison of ion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ponderomotive Energy
In strong-field laser physics, ponderomotive energy is the cycle-averaged quiver energy of a free electron in an electromagnetic field. Equation The ponderomotive energy is given by :U_p = , where e is the electron charge, E is the linearly polarised electric field amplitude, \omega_0 is the laser carrier frequency and m is the electron mass. In terms of the laser intensity I, using I=c\epsilon_0 E^2/2, it reads less simply: :U_p \cdot , where \epsilon_0 is the vacuum permittivity. For typical orders of magnitudes involved in laser physics, this becomes: : U_p (\mathrm) = 9.33 \cdot I(10^\ \mathrm^2) \cdot \lambda^2(\mathrm^2) , where the laser wavelength is \lambda= 2\pi c/\omega_0, and c is the speed of light. The units are electronvolts (eV), watts (W), centimeters (cm) and micrometers (μm). Atomic units In atomic units, e=m=1, \epsilon_0=1/4\pi, \alpha c=1 where \alpha \approx 1/137. If one uses the atomic unit of electric field,CODATA Valueatomic unit of electric fie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrashort Pulse
In optics, an ultrashort pulse, also known as an ultrafast event, is an electromagnetic pulse whose time duration is of the order of a picosecond (10−12 second) or less. Such pulses have a broadband optical spectrum, and can be created by mode-locked oscillators. Amplification of ultrashort pulses almost always requires the technique of chirped pulse amplification, in order to avoid damage to the gain medium of the amplifier. They are characterized by a high peak intensity (or more correctly, irradiance) that usually leads to nonlinear interactions in various materials, including air. These processes are studied in the field of nonlinear optics. In the specialized literature, "ultrashort" refers to the femtosecond (fs) and picosecond (ps) range, although such pulses no longer hold the record for the shortest pulses artificially generated. Indeed, x-ray pulses with durations on the attosecond time scale have been reported. The 1999 Nobel Prize in Chemistry was awar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoelectron Spectrum
Photoemission spectroscopy (PES), also known as photoelectron spectroscopy, refers to energy measurement of electrons emitted from solids, gases or liquids by the photoelectric effect, in order to determine the binding energies of electrons in the substance. The term refers to various techniques, depending on whether the ionization energy is provided by X-ray, EUV or UV photons. Regardless of the incident photon beam, however, all photoelectron spectroscopy revolves around the general theme of surface analysis by measuring the ejected electrons. Types X-ray photoelectron spectroscopy (XPS) was developed by Kai Siegbahn starting in 1957 and is used to study the energy levels of atomic core electrons, primarily in solids. Siegbahn referred to the technique as "electron spectroscopy for chemical analysis" (ESCA), since the core levels have small chemical shifts depending on the chemical environment of the atom that is ionized, allowing chemical structure to be determined. Siegba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic, Molecular, And Optical Physics
Atomic, molecular, and optical physics (AMO) is the study of matter–matter and light–matter interactions, at the scale of one or a few atoms and energy scales around several electron volts. The three areas are closely interrelated. AMO theory includes classical, semi-classical and quantum treatments. Typically, the theory and applications of emission, absorption, scattering of electromagnetic radiation (light) from Excited state, excited atoms and molecules, analysis of spectroscopy, generation of lasers and masers, and the optical properties of matter in general, fall into these categories. Atomic and molecular physics Atomic physics is the subfield of AMO that studies atoms as an isolated system of electrons and an atomic nuclei, atomic nucleus, while molecular physics is the study of the physical properties of molecules. The term ''atomic physics'' is often associated with nuclear power and nuclear bombs, due to the synonymous use of ''atomic'' and ''nuclear'' i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
