Precise measurement of hyperfine structure in the $ \rm {3\,S_{1/2}} $ state of $ \rm{^7Li} $

Abstract

We report a precise measurement of hyperfine structure in the $ \rm {3\,S_{1/2}} $ state of the odd isotope of Li, namely $ \rm {^7Li} $. The state is excited from the ground $ \rm {2\,S_{1/2}} $ state (which has the same parity) using two single-photon transitions via the intermediate $ \rm {2\,P_{3/2}} $ state. The value of the hyperfine constant we measure is $ A = 93.095(52)$ MHz, which resolves two discrepant values reported in the literature measured using other techniques. Our value is also consistent with theoretical calculations.