Determination of the Quadrupole Frequency Shift of the 2S1/2 - 2D5/2 Transition in 88Sr+ at 674 nm

In preparation for an absolute frequency measurement referenced directly to the NPL caesium frequency fountain, the authors have made a measurement of the quadrupole shift of the 674 nm transition in
⁸⁸
Sr
⁺
. This allows a determination of the quadrupole moment of the
²
D
_5/2
level, which is compared with Cowan code calculations