Radiative Decay Rates in ${\mathrm{Hg}}^{+}$ from Observations of Quantum Jumps in a Single Ion

Radiative decay rates connecting the lowest four energy levels of ${}_{}{}^{198}{}_{}{}^{}\mathrm{Hg}_{}^{+}{}_{}{}^{}$ have been derived solely from an analysis of the fluctuations (quantum jumps) of the laser-induced fluorescence of the 194-nm first resonance transition of a single ion confined in a Paul trap. The natural linewidth of the 194-nm first resonance transition was also measured. The measured decay rates and branching ratios are in satisfactory agreement with theory.