Stark Effect on Cesium-133 Hyperfine Structure

The change of the hyperfine-structure separation energy caused by an electric field has been measured in ${\mathrm{Cs}}^{133}$ by the atomic-beam magnetic-resonance method. The shift of the $(F=4, m_F=0)\leftrightarrow (F=3, m_F=0)$ transition frequency in the electric field $\mathcal{E}$ is given by $\Delta \left(\mathcal{E}\right)=-2.29\mathrm{}\times {10}^{-6\mathrm{}}(1\mathrm{}\pm 0.03){\mathcal{E}}^2 \mathrm{cps},$ where $\mathcal{E}$ is in volts/cm. This number is 2.8 times the value predicted from the atomic polarizability measurements of Scheffers and Stark if a simplified theory which neglects hyperfine-structure perturbations of the ground-state wave functions is used.