Measurement of the hyperfine splitting of the 6S$_{1/2}$ level in rubidium

TL;DR

This paper reports precise measurements of the hyperfine splitting in the 6S1/2 level of rubidium isotopes using two-photon spectroscopy, revealing a hyperfine anomaly related to nuclear magnetization distribution.

Contribution

First measurement of hyperfine splitting in the 6S1/2 level of rubidium isotopes using two-photon absorption spectroscopy, highlighting the hyperfine anomaly due to nuclear magnetization effects.

Findings

Magnetic dipole constant A for 85Rb is 239.18 MHz.

Magnetic dipole constant A for 87Rb is 807.66 MHz.

Hyperfine anomaly difference is -0.0036, indicating nuclear magnetization effects.

Abstract

We present a measurement of the hyperfine splitting of the 6S$_{1/2}$ excited level of rubidium using two photon absorption spectroscopy in a glass cell. The values we obtain for the magnetic dipole constant A are 239.18(03) MHz and 807.66(08) MHz for $^{85}$Rb and $^{87}$Rb, respectively. The combination of the magnetic moments of the two isotopes and our measurements show a hyperfine anomaly in this atomic excited state. The observed hyperfine anomaly difference has a value of $_{87}\delta_{85}=-0.0036(2)$ due to the finite distribution of nuclear magnetization, the Bohr-Weisskopf effect.