Selection rule
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In physics and chemistry, a selection rule, or transition rule, formally constrains the possible transitions of a system from one quantum state to another. Selection rules have been derived for electr
The infrared spectrum of HCl gas
Hyperfine structure
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In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate electronic energy levels and the resulting splittings in those electronic energy levels of atoms, molecules, a
Selection rule
…momentum quantum number. Which transitions are allowed is based on the hydrogen-like atom. The symbol ↮ is used to indicate a forbidden transition. In hyperfine structure, the total angular momentum of the atom is F = I + J , where I is the nuclear spin angular momentum and J is the total angular momentum of the electron(s…
Hyperfine splitting in ferromagnetic cobalt at 3.5 K, observed by quasielastic neutron scattering.