Precision measurement of the 5 ~2S_(1/2) — 4 ~2D_(5/2) quadrupole transition isotope shift between ~(88)Sr~+ and ~(86)Sr~+

摘要

We present a high-precision measurement of the isotope shift of the narrow quadrupole-allowed 5 ~2S_(1/2) —4 ~2D_(5/2) transition in ~(86)Sr~+ relative to the most abundant isotope ~(88)Sr~+. This was accomplished using high-resolution laser spectroscopy of individual trapped ions, and the measured shift is Δ v_(meas)~(88,86) =570.281(4) MHz. We also tested a recently developed and successful method for ab initio calculation of isotope shifts in alkali-metal-like atomic systems against this measurement, and our initial result of Ov_(cal)~(88,86) =457(28) MHz is also presented. While the measurement and the calculation are in broad agreement, there is a clear discrepancy between them, and we believe that the specific mass shift was underestimated in our calculation. Our measurement provides a stringent test for further refinements of theoretical isotope shift calculation methods for atomic systems with a single valence electron.