hyperfine transition frequency
1Hyperfine structure — In atomic physics, hyperfine coupling is the weak magnetic interaction between electrons and nuclei. Hyperfine coupling causes the hyperfine splitting of atomic or molecular energy levels. The totality of energy levels spawned by hyperfine… …
2Orders of magnitude (frequency) — To help compare different orders of magnitude, the following list describes various frequencies, which is measured in Hertz. Factor (Hz) Multiple Value Item 10−18 1 attohertz (aHz) 2.29 aHz The Hubble Constant (once in 13.8 billion years) 10−15 1 …
3Second — This article is about the unit of time. For other uses, see Second (disambiguation). A light flashing approximately once per second. The second (SI unit symbol: s; informal abbreviation: sec) is a unit of measurement of time, and is the… …
4Conventional electrical unit — A conventional electrical unit (is also know as a electrical symbol) (or simply conventional unit where there is no risk of ambiguity) is a unit of measurement in the field of electricity which is based on the conventional values of the Josephson …
5spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
6Atomic clock — Nuclear clock redirects here. For the clock as a measure for risk of catastrophic destruction, see Doomsday Clock. For a clock updated by radio signals (commonly but inaccurately called an atomic clock ), see Radio clock. For the album by Zion I …
7Hydrogen line — For hydrogen lines in general, see Hydrogen spectral series. The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This… …
8Caesium — xenon ← caesium → barium Rb ↑ Cs ↓ Fr …
9Pioneer plaque — The Pioneer plaques are a pair of gold anodized aluminum plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message from humanity, in case either Pioneer 10 or 11 are intercepted by… …
10Rubidium standard — A rubidium standard is a frequency standard in which a specified hyperfine transition of electrons in rubidium 87 atoms is used to control the output frequency. A rubidium standard consists of a gas cell, which has an inherent long term… …
