Systematics of quadrupole moments and energies
We define the "quadrupole ratio" r_{Q}=\dfrac{Q_{0}(S)}{Q_{0}(B)} where Q_{0}(S) is the intrinsic quadrupole moment obtained from the static quadrupole moment of the 2_{1}^{+} state of an even-even nucleus and Q_{0}(B) the intrinsic quadrupole moment obtained from B(E2)_{0\rightarrow2} . In both cases we assume a simple rotational formula connecting the rotating frame to the laboratory frame. The quantity r_{Q} would be one if the rotational model were perfect and the energy ratio E(4)/E(2) would be 10/3. In the simple vibrational model, r_{Q} would be zero and E(4)/E(2) would be two. There are some regions where the rotational limit is almost met and fewer where the vibrational limit is also almost met. For most cases, however, it is between these two limits, i.e. 0<|r_{Q}|<1 . There are a few cases where r_{Q} is bigger than one, especially for light nuclei. In most cases the quadrupole ratio is positive but there are two regions with negative ratios. The first case is that of light nuclei and the second has certain nuclei close to ^{208} Pb.