Three-step laser excitation of the 6p3/2ns, nd, ng autoionizing Rydberg levels via the 6p5f 1/2[5/2]2 level of lead

Odd parity autoionizing Rydberg levels of atomic lead in the energy region above the 6p(1/2) ionization threshold have been investigated using three-step laser excitation in conjunction with an atomic beam apparatus. The 6p(3/2)ns ( J = 1, 2), 6p(3/2)nd ( J = 1, 2, 3) and 6p(3/2)ng ( J = 2, 3) levels have been observed from the 6p5f 1/2[5/2](2) intermediate level. Energy values and FWHM of forty levels belonging to the 6p(3/2)ns, 6p(3/2)nd and 6p(3/2)ng configurations are presented. Six levels based on the 6p(3/2)ng (5, 13 less than or equal to n less than or equal to 15) configurations and three levels attached to the 6p(3/2)8d configuration are reported for the first time. The present study of the low-lying autoionizing levels attached to the 6p(3/2)5g ( J = 2, 3) configuration completes the series adjacent to the 6p(1/2) limit.