Fractional electric quadrupole shifts due to the multipoles up to k = 10 for the (a) E2 and (b) E3 transitions. The ion is off centered by a distance of 0.1 μm (green) and 10 μm (black). The harmonic potential gives a spatially independent |ΔνQ/νo|. The reported fractional accuracies lie within the grey bands and so far the best accuracies are 1.1 × 10−16[8] and 5 × 10−17[18] for the E2 and E3 transitions, respectively. |