Lifetimes of some highly excited levels in the Pb-I spectrum measured by the hanle method
Natural lifetimes of some highly excited levels in the Pb-I spectrum have been measured by the zero field level crossing (Hanle) method. The levels were reached by optical excitation from the metastable 6p2 3P2 and 6p2 3P1 states, were a considerable population had been created by means of adc discharge in a Pb atomic beam. An atomic beam source producing atoms in metastable states is described. For the lifetimes τ of the investigated levels we find:τ(6p(1/2)6d3D1)=3.74(28) ns,τ(6p(1/2)6d3F2)=25.8(1.3) ns,τ(6p(1/2)6d3D2)=4.17(−31)(−49) ns,τ(6p(1/2)6d3F3)=6.08(26) ns,τ(6p(3/2)7s)3P2=5.85(27) ns. These results are compared with lifetimes derived from oscillator strengths given in the literature.