The coupled monopole and $\beta$ and $\gamma$ quadrupole $T=0\mathrm{}$ vibrations in $\mathrm{sd}$-shell nuclei are studied within the generator-coordinate method, together with a scaling assumption. In contrast to heavier deformed nuclei, the splitting due to the nuclear deformation appears as the dominant mechanism in the spreading of the $E2\mathrm{}$ strength. The available experimental data support our analysis.

• Received 18 July 1977

DOI:https://doi.org/10.1103/PhysRevLett.39.922