hyperfine spectrum
21Hydrogen 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… …
22Rotational spectroscopy — Part of the rotational vibrational spectrum of carbon monoxide (CO) gas (from FTIR), showing the presence of P and R branches. Frequency is on the x axis, and absorbance on the y axis. Rotational spectroscopy or microwave spectroscopy studies the …
23Diazenylium — N2H+, known as diazenylium, was one of the first ions to be observed in interstellar clouds. Since then, it has been observed for a variety of purposes in several different types of interstellar environments. It gives astronomers information… …
24Karl Meissner — Karl Wilhelm Meissner (December 15, 1891 in Reutlingen, Württemberg ndash; April 13, 1959 on the cruise ship Herzthrombose sailing to Europe) was a German American physicist specializing in hyperfine spectroscopy. He spent the greater part of his …
25Caesium — xenon ← caesium → barium Rb ↑ Cs ↓ Fr …
26Energy level — A quantum mechanical system or particle that is bound that is, confined spatially can only take on certain discrete values of energy. This contrasts with classical particles, which can have any energy. These discrete values are called energy… …
27Lamb, Willis Eugene, Jr. — ▪ 2009 American physicist born July 12, 1913, Los Angeles, Calif. died May 15, 2008, Tucson, Ariz. was corecipient, with Polykarp Kusch, of the 1955 Nobel Prize for Physics for experimental work that spurred refinements in the quantum… …
28Maser — For other uses, see Maser (disambiguation). A hydrogen radio frequency discharge, the first element inside a hydrogen maser (see description below) A maser is a device that produces coherent electromagnetic waves through amplification by… …
29Mössbauer 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… …
30Doppler cooling — is a mechanism that can be used to trap and cool atoms. The term is sometimes used synonymously with laser cooling, though laser cooling includes other techniques. Contents 1 History 2 Brief Explanation 3 Detailed Explanation …
