The transition quadrupole moments $Q_t$ for the superdeformed band in ${}^{40}\mathrm{Ca}$ have been determined through thin-target Doppler-shift attenuation analyses. A best-fit value of $Q_t=1.30\mathrm{}\pm 0.05$ $e\mathrm{b}$ is obtained when a single value is assumed for the entire band. Fitting separate quadrupole moments for in-band transitions decaying from the high-spin states and the presumably admixed low-spin states results in $Q_t(\mathrm{high}{)=1.81\mathrm{}}_{-0.26}^{+0.41\mathrm{}}$ $e\mathrm{b}$ and $Q_t(\mathrm{low}{)=1.18\mathrm{}}_{-0.05}^{+0.06\mathrm{}}$ $e\mathrm{b},$ respectively. $Q_t$ values extracted for individual transitions in a Doppler-broadened line-shape analysis also indicate smaller $Q_t$ values at lower spins. These results are consistent with the interpretation of this band as an eight-particle–eight-hole superdeformed band with a significant admixture of less-collective configurations at low spins.

• Received 21 January 2003

DOI:https://doi.org/10.1103/PhysRevC.67.041303