# What is Hyperfine structure: Definition + 15 Threads

In atomic physics, hyperfine structure is defined by small shifts in otherwise degenerate energy levels and the resulting splittings in those energy levels of atoms, molecules, and ions, due to interaction between the nucleus and electron clouds.
In atoms, hyperfine structure arises from the energy of the nuclear magnetic dipole moment interacting with the magnetic field generated by the electrons and the energy of the nuclear electric quadrupole moment in the electric field gradient due to the distribution of charge within the atom. Molecular hyperfine structure is generally dominated by these two effects, but also includes the energy associated with the interaction between the magnetic moments associated with different magnetic nuclei in a molecule, as well as between the nuclear magnetic moments and the magnetic field generated by the rotation of the molecule.
Hyperfine structure contrasts with fine structure, which results from the interaction between the magnetic moments associated with electron spin and the electrons' orbital angular momentum. Hyperfine structure, with energy shifts typically orders of magnitudes smaller than those of a fine-structure shift, results from the interactions of the nucleus (or nuclei, in molecules) with internally generated electric and magnetic fields.

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1. ### I How to work in the |F,m_F> states in hyperfine structure

Suppose that we have two atoms with one proton one electron each, and these electrons interact with each other. The states for the electrons are the singlet(S=0) and the triplet states(S=1). My question is if i have to keep the nuclear spin of the protons parallel when i write the states, for...
2. ### A Eigenvalues of Hyperfine Hamiltonian

I was reading a paper on Radical-Pair mechanism (2 atoms with 1 valence electron each) and the author used the hyperfine hamiltonian $$H_{B}=-B(s_{D_z}+s_{A_z})+As_{D_x}I_x+As_{D_y}I_y+as_{D_z}I_z$$ and found the following eigenvalues: a/4 (doubly degenerate) , a/4±B , (-a-2B±2√(A^2+B^2)) ...
3. ### I Hyperfine structure - Hamiltonian and bases

Hi, could you please explain me, how to copmute the yellow parts? Thank you very much.
4. ### Determine fine-structure constant

Homework Statement The figure below shows the hyperfine structure in the transition 6s $^2S_{1/2}$ - 8p $^2P_{3/2}$ in 115In (I = 9/2). The measurement is made using a narrow-band tunable laser and a collimated atomic beam; hence the Doppler width is greatly reduced. The 6 components shown have...
5. ### I List of hyperfine structure of the elements?

If caesium 133 frequency for its hyperfine structure is 9 192 631 770, and hydrogen is 1 420 405 751.7667 what are the frequencies for the other elements and their isotopes? Is there a list on line some were because this would be a long list. Any help on where to look on line would be...
6. D

### I How Does Rubidium's Electron Spin Affect Its Energy Levels?

Hello everybody, while I tried to understand the Rubidium level scheme, I realized that I have some issues concerning the energy levels in general... If in addition to the orbital Momentum the spin momentum of an electron is considered for example the p level splits to the 2P1/2-level and the...
7. ### Hyperfine structure of deuterium

Homework Statement Hi everybody! Here is the problem: Hyperfine splitting of Deuterium Balmer alpha line: Consider the ##3p_{3/2}## to ##2s_{1/2}## transition in deuterium. Find the number of transition lines and their frequency shifts with respect to the transition without hyperfine...
8. ### Energy splitting in hyperfine structure

Homework Statement I've been given the worked answer to a very similar question, but there's a step I don't understand so I can't apply it. My question asks: An energy level with ##J=\frac{11}{2}## has six hyperfine sub-levels with these relative energies...
9. ### A Hyperfine structure transition of Cs-133: calculation?

I'm looking for the theoretical calculation of the hyperfine structure transition frequency of Ca-133 which is used in atomic clocks to define the second according to SI-Units. Google, Google... there is a lot about the hyperfine Hamiltonian of hydrogen, but couldn't find none about that of...
10. ### Hyperfine structure in hydrogen

Consider the Dirac equation for bounded electron in hydrogen atom. I am trying to get a clear physical explanation for all mathematical terms that appear in the Hamiltonian and energy spectrum. Kinetic and Coulombic potential and rest energies are the first terms and easy to identify. Then we...
11. ### Hyperfine Structure of $^133Cs$: Find I & J

Homework Statement A transition happens for ##\lambda = 494nm## in the Cesium ions (##^133 Cs##) between a term in the ##5p^5 6s## configuration and term in the ##5p^5 6p## configuration. Five components are observed with the following energies (relative to the transition of least energy): 0...
12. ### Fine structure, and hyperfine structure

Hello... I was just reading about that, and I have one question. In the chapter I've jut read about, the overall headline is about one electron atoms, so I was just wondering, since the overall equation got Z (Atomic number) in it, if this was for larger atoms as well, or ONLY one electron...
13. ### Why is the Hyperfine Structure of Hypogen Simpler Than That of Hydrogen?

Homework Statement Hyperfine structure is the splitting of energy levels due to the coupling of the magnetic moment of the atomic nucleus and the electron’s total angular momentum. In a hypothetical atom called “hypogen” the electron is replaced by a negatively charged pion (π-) which has...
14. ### Hydrogen spectrum hyperfine structure

A detailed picture of the Hydrogen red line shows a lot of detail: The difference in the 2 largest peaks is the fine structure, the lamb shift is clearly noted, but what are the other 2 bumps just below the lamb shift in the upper chart. I was thinking hyperfine, but I don't think that...
15. ### How Do Electron Spin and Proton Movement Influence Hydrogen Atom's Structure?

Homework Statement I am trying to see if I understand these corrections to the hydrogen atom: To explain the fine structure correction, we go to the electrons frame of reference, in which the proton is moving with velocity v. This produces a magnetic field according to Maxwell's equations the...