Measurement of the B+and Al+intercombination and Sc12+forbidden transition rates at a heavy-ion storage ring

Electric-dipole intercombination and forbidden transitions have been optically observed with ions circulating in a storage ring, and atomic lifetimes determined. For the level in the Be-like ion , the measured lifetime of ms corresponds to a transition probability of . This result ties in with experimental work on the neighbouring ion and with recent calculations. For the corresponding level in the Mg-like ion , a lifetime of s (transition rate ) has been measured, corroborating earlier experiments but not the more recent calculations. The transition probability of the M1/E2 transition between the fine-structure levels of the ground state in F-like has been determined as , in agreement with the results of semi-empirically corrected multi-configuration Dirac-Fock calculations.