Two-step laser excitation of the even-parity Rydberg levels of lead

Abstract

We report new data for the even-parity, J=0, 1 and 2 levels of neutral lead using a two-step laser excitation technique in conjunction with a thermionic diode detector. The Rydberg series 6pnp( 1/2 , 3/2)2, (10<or=n<or=56); 6pnp( 1/2 , 3/2)1, (10<or=n<or=25); 6pnp( 1/2 , 1/2 )0, (10<or=n<or=36) and 6pnf( 1/2 , 5/2)2, (7<or=n<or=29) as well as four perturbing levels, 6p7p(3/2, 1/2 )1,2 and 6p7p(3/2, 3/2)1,2 have been identified. The 6pnp( 1/2 , 1/2 )0 series possesses a constant quantum defect implying its unperturbed behaviour. For the parametrization of the perturbed Rydberg series, the multichannel quantum-defect theory analysis has been performed using three channels for the J=1 levels and four channels for the J=2 levels.