A Search for an Excited Kp=0+ Rotational Band in 24Mg

Abstract

A search is described for an excited Kn = 0+ rotational band based on the 6· 44 MeV level of 24Mg. Mean nuclear lifetimes have been measured by the Doppler shift attenuation method using the 12C('60,a)24Mg reaction and the results are 't'm = 66±29, 28±7 and 13±3 fs for levels at 6'44, 8·65 and 10· 58 MeV respectively. The absolute transition rates found for the y decays from the 6·44 and 8·65 MeV levels are in good agreement with the results of shell model calculations if it is assumed that these levels are the 0+ and 2 + members respectively of the excited Kn = 0+ rotational band. Based on this assumption, a result Qoo = 0·48 ±0·08b is obtained for the intraband quadrupole moment. From a study of the 23Na(p, y) reaction, it is established that the J = 4 levels at 12· 63 and 13·05 MeV do not decay by enhanced E2 transitions to the 8· 65 MeV level. This suggests that neither of these levels is the 4 + member of the excited Kn = 0+ rotational band. An assignment of J" = 4+ is made to one member of the doublet at 10·58 MeV.