We propose a new class of atomic microwave clocks based on the hyperfine transitions in the ground state of aluminum or gallium atoms trapped in optical lattices. For such elements magic wavelengths exist at which both levels of the hyperfine doublet are shifted at the same rate by the lattice laser field, cancelling its effect on the clock transition. A similar mechanism for the magic waveleng...

Measuring the hyperfine structure (HFS) of long-lived P2 states of divalent atoms may offer the opportunity of extracting relatively unexplored nuclear magnetic octupole and electric hexadecapole moments. Here, using relativistic many-body methods of atomic structure and the nuclear shell model, we evaluate the effect of these higher nuclear moments on the hyperfine structure. We find that the ...

A new result for the hadronic vacuum polarization correction to the muonium hyperfine splitting (HFS) is presented: ∆ν(had – vp) = (0.233 ± 0.003) kHz. Compared with previous calculations, the accuracy is improved by using the latest data on e+e− → hadrons. The status of the QED prediction for HFS is discussed.

The largest uncertainty in calculations of hydrogen ground-state hyperfine splitting comes from corrections due to proton stucture. We review these corrections, with special mention of the inelastic, or polarizability, corrections which have been recently re-evaluated. Summing up the arguably best current values for the calculated corrections leaves us 1–2 ppm short of the experimental data. We...

Terms contributing to the hyperfine structure of the muonium ground state at the level of few tenths of kHz have been evaluated. The α(Zα) radiative correction has been calculated numerically to the precision of 0.02 kHz. Leading ln(Zα) terms of order α(Zα), n = 1, 2, 3, and some relativistic corrections have been evaluated analytically. The theoretical uncertainty is now reduced to 0.17 kHz. A...

Measuring the hyperfine structure HFS of long-lived P2 states of divalent atoms may offer the opportunity of extracting relatively unexplored nuclear magnetic octupole and electric hexadecapole moments. Here, using relativistic many-body methods of atomic structure and the nuclear shell model, we evaluate the effect of these higher nuclear moments on the hyperfine structure. We find that the se...

A theoretical model of hyperfine spectra of nuclear spin conversion of molecular isomers has been developed. The model takes into account the nuclear spin-spin and spin-rotation interactions, as well as the saturation of intramolecular mixing of molecular ortho and para states. The model has been applied to hyperfine spectra of nuclear spin conversion in CH3F molecules subjected to an external ...