Second-order effects on the hyperfine structure of $P$ states of alkali-metal atoms

TL;DR

This paper investigates second-order hyperfine effects in alkali-metal atoms' P states, revealing significant corrections especially in lithium, which impact the precision of hyperfine structure measurements.

Contribution

It provides a detailed analysis of second-order M1-M1 and M1-E2 effects on hyperfine structure, highlighting their importance and quantifying corrections in alkali-metal atoms.

Findings

Significant second-order effects in lithium's hyperfine structure.

9 sigma correction to lithium's HFS constant from experimental value.

Results serve as higher precision references for future experiments.

Abstract

We analyze second-order $M1$-$M1$ and $M1$-$E2$ effects to the hyperfine structure (HFS) of the lowest energy $P$ states of alkali-metal atoms arising from the coupling of the two ($J=1/2,3/2$) fine-structure levels through the hyperfine interaction. We find these effects to be especially sizable in Li, leading to a $9\sigma$ correction to the most accurate reported experimental value of the $A(P_{1/2})$ HFS constant of $^7$Li [D. Das and V. Natarajan, J. Phys. B \textbf{41}, 035001 (2008)]. For the remaining alkali-metal systems, the results tabulated within may be referenced as higher precision is sought in experimental determination of the HFS constants.