The hyperfine structure of the ${}^2{S}_{1/2}{-}^2{D}_{5/2}$ quadrupole transition at 674 nm in ${}^{87}{\mathrm{Sr}}^{+}$ has been observed. The ion was confined in a Paul trap and cooled using laser radiation at 422 and 1092 nm. The quadrupole transition was observed by monitoring quantum jumps in the 422-nm fluorescence. The odd isotope of strontium has “clock” transitions independent of the first-order Zeeman shift and the ${}^2{D}_{5/2}$ state hyperfine structure constants have been determined as $A_{D_{5/2}}=2.1743\mathrm{}\left(14\right)\mathrm{}\mathrm{MHz}$ and $B_{D_{5/2}}=49.11\mathrm{}\left(6\right)\mathrm{}\mathrm{MHz}.$ Standard uncertainties have been added in parentheses. These values allow the second-order Zeeman shifts to be calculated. The ${}^{88}{\mathrm{Sr}}^{+}{-}^{87}{\mathrm{Sr}}^{+}$ isotope shift for the 674-nm quadrupole transition has been measured to be 247.99(4) MHz.

• Received 29 July 2002

DOI:https://doi.org/10.1103/PhysRevA.67.013402