hyperfine structure
Noun
Meaning
hyperfine structure (plural hyperfine structures)
(physics) a closely spaced structure of lines in the spectrum of an atom or molecule due to nuclear isotopic effects and/or to nuclear spin
Examples
In June 2011, trapped 309 antihydrogen atoms, up to 3 simultaneously, for up to 1,000 seconds. citation citation They then studied its hyperfine structure, gravity effects, and charge.
Before Essen's invention, the second was defined on the orbit of the Earth around the Sun ; he changed it in 1967 to be based on the hyperfine structure of the caesium-133 atom.