Lifetimes and transition probabilities in Cu ii

Radiative lifetimes of some of the levels in the Cu ii 3d94p and 3d95s configurations have been measured to accuracies of 10–20% by using a delayed-coincidence technique. Relative line strengths for the 3d94s–3d94p and 3d94p–3d95s arrays have been determined both theoretically and experimentally. The theoretical line strengths are based on intermediate-coupling calculations, and the experimental ones are based on branching-ratio measurements and the J-file sum rule. Good agreement between the two sets of values is obtained; agreement is more satisfactory for the 4s–4p array than for the 4p–5s array. The experimental line strengths are estimated to be accurate to 10% for the 4s–4p array and to 30% for the 4p–5s array. Transition probabilities are determined by normalizing the experimental line strengths to an absolute scale by using the measured lifetimes.