rf Spectroscopy on Coherent Populations Using Quantum Beats

Abstract

The resonant interaction between an rf electric field and a coherent atomic state is studied by monitoring the field-induced changes in the quantum beats after a beam-foil collision. A theory for the interaction is discussed and a preliminary measurement of the fine-structure interval $J=\frac{3}{2}$ to $J=\frac{5}{2}$ in the $n=4\mathrm{}$ state of hydrogen is presented.