The hyperfine intervals of the ${}^{133}\mathrm{Cs}$ $7d{}^{2}D_{3∕2}$ manifold are measured using two-photon resonant laser-induced-fluorescence of an effusive cesium beam. A radio-frequency phase modulation technique directly references the relative frequency scale to the ground hyperfine splitting of ${}^{87}\mathrm{Rb}$. The ${}^{133}\mathrm{Cs}$ $7d{}^{2}D_{3∕2}$ hyperfine intervals are used to generate the magnetic dipole coupling constant $A=7.36\pm 0.03\mathrm{MHz}$ and electric quadrupole coupling constant $B=-0.1\pm 0.2\mathrm{MHz}$. The $A$ coupling constant agrees with a previous measurement, but with an improvement in resolution that is sufficient to serve as a benchmark value for testing high-precision theory. The result for the $B$ coupling constant is the first constraint placed on this parameter.

• Received 11 April 2008
• Publisher error corrected 30 June 2008

DOI:https://doi.org/10.1103/PhysRevA.77.062505