Experimental study of configuration mixing effects on the lifetimes of 1s22s6l levels in Be-like O

The lifetimes of 11 levels in the 2s6d, 6f and 6g configurations in O V have been determined using the beam-foil technique. The new CCD detection system is described and its advantages for atomic lifetime measurements are discussed. The experimental results are compared with ab initio theoretical and semiempirical values calculated by the superposition-of-configurations method. Configuration interactions between 2s6f and 2p4d and between 2s6g and 2p4f are found to have a significant influence on the lifetimes and an accurate treatment of this level mixing is necessary to bring theory and experiment into agreement. (orig.)