3-STEP LASER EXCITATION OF THE 6P(3 2)NS, ND J=1,2,3 AUTOIONIZING RYDBERG LEVELS OF LEAD/

We report here first measurements of the odd-parity 6p(3/2)ns J = 1,2 and 6p(3/2)nd J = 0, 1, 2, 3 autoionizing Rydberg levels of lead using a three-step laser excitation scheme in conjunction with an atomic be am apparatus. Four initial levels 6P(3/2)7P(1/2,3/2) J = 1, 2 were cho sen for the excitation of the final levels. The assignments have been made using the j(1) K-coupling scheme for the observed levels. The Ryd berg series 6pnd3/2[1/2](0,1) (13 less than or equal to n less than or equal to 38), 3/2[3/2](2) (16 less than or equal to n less than or eq ual to 73), 3/2[5/2](2,3) (13 less than or equal to n less than or equ al to 37) and 3/2[7/2](3) (16 less than or equal to n less than or equ al to 39) as well as 6p(3/2)ns3/2[3/2](1,2) (14 less than or equal to n less than or equal to 40) are reported. All the observed series exhi bit constant quantum defects with respect to the ionization potential value 73 900.65 + 0.05 cm(-1). The full widths at half the maximum Gam ma of the observed levels are also reported.