Atomic units — (au) form a system of units convenient for atomic physics, electromagnetism, and quantum electrodynamics, especially when the focus is on the properties of electrons. There are two different kinds of atomic units, which one might name Hartree… … Wikipedia
Atomic physics — (or atom physics) is the field of physics that studies atoms as an isolated system of electrons and an atomic nucleus. It is primarily concerned with the arrangement of electrons around the nucleus and the processes by which these arrangements… … Wikipedia
Atomic theory — Atomic model redirects here. For the unrelated term in mathematical logic, see Atomic model (mathematical logic). This article is about the historical models of the atom. For a history of the study of how atoms combine to form molecules, see… … Wikipedia
Atomic hydrogen welding — (AHW) is an arc welding process that uses an arc between two metal tungsten electrodes in a shielding atmosphere of hydrogen. The process was invented by Irving Langmuir in the course of his studies of atomic hydrogen. The electric arc… … Wikipedia
atomic theory — n 1) a theory of the nature of matter: all material substances are composed of minute particles or atoms of a comparatively small number of kinds and all the atoms of the same kind are uniform in size, weight, and other properties called also… … Medical dictionary
atomic theory — n. the theory that all material objects and substances are composed of atoms, and that various phenomena are explained by the properties and interactions of these atoms … English World dictionary
Atomic orbital — The shapes of the first five atomic orbitals: 1s, 2s, 2px, 2py, and 2pz. The colors show the wave function phase. These are graphs of ψ(x,y,z) functions which depend on the coordinates of one electron. To see the elongated shape of ψ(x,y,z)2… … Wikipedia
Atomic number — See also: List of elements by atomic number An explanation of the superscripts and subscripts seen in atomic number notation. In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the… … Wikipedia
Atomic line filter — A potassium Faraday filter designed, built and photographed by Jonas Hedin for making daytime LIDAR measurements at Arecibo Observatory.[1] An atomic line filter (ALF) is an advanced optical band pass filter used in the physical sciences for… … Wikipedia
Atomic orbital model — The Atomic Orbital Model is the currently accepted model of the electrons in an atom. It is sometimes called the Wave Mechanics Model. In the atomic orbital model, the atom consists of a nucleus surrounded by orbiting electrons. These electrons… … Wikipedia
Atomic nucleus — A figurative depiction of the helium 4 atom with the electron cloud in shades of gray. In the nucleus, the two protons and two neutrons are depicted in red and blue. This depiction shows the particles as separate, whereas in an actual helium atom … Wikipedia