excited atom density
41Laser — For other uses, see Laser (disambiguation). United States Air Force laser experiment …
42Spontaneous emission — is the process by which a light source such as an atom, molecule, nanocrystal or nucleus in an excited state undergoes a transition to the ground state and emits a photon. Spontaneous emission of light or luminescence is a fundamental process… …
43Xenon — (PronEng|ˈzɛnɒn [Xenon, entry in the Oxford English Dictionary, prepared by J. A. Simpson and E. S. C. Weiner, vol. 20, second edition, Oxford: Clarendon Press, 1989. ISBN 0 19 861232 X (vol. 20), ISBN 0 19 861186 2 (set.)] or IPAlink en|ˈziːnɒn… …
44Mössbauer spectroscopy — A Mössbauer absorption spectrum of 57Fe Mössbauer spectroscopy is a spectroscopic technique based on the Mössbauer effect. This effect, discovered by Rudolf Mössbauer in 1957, consists in the recoil free, resonant absorption and emission of gamma …
45chemical compound — Introduction any substance composed of identical molecules consisting of atoms (atom) of two or more chemical elements (chemical element). All the matter in the universe is composed of the atoms of more than 100 different chemical elements …
46Electron configuration — Electron atomic and molecular orbitals Simp …
47Phonon — For KDE Software Compilation 4 s multimedia framework, see Phonon (KDE). Normal modes of vibration progression through a crystal. The amplitude of the motion has been exaggerated for ease of viewing; in an actual crystal, it is typically much… …
48chemical bonding — ▪ chemistry Introduction any of the interactions that account for the association of atoms into molecules, ions, crystals, and other stable species that make up the familiar substances of the everyday world. When atoms approach one another …
49Plasma (physics) — For other uses, see Plasma. Plasma lamp, illustrating some of the more complex phenomena of a plasma, including filamentation. The colors are a result of relaxation of electrons in excited states to lower energy states after they have recombined… …
50Mössbauer effect — Physics. the phenomenon in which an atom in a crystal undergoes no recoil when emitting a gamma ray, giving all the emitted energy to the gamma ray, resulting in a sharply defined wavelength. [1955 60; named after R. MÖSSBAUER] * * * ▪ physics… …
