Resonance ionization spectroscopy and analysis on even-parity states of Pb

Abstract

Two-color resonance ionization spectroscopies of Pb, even parity, J=0, 1, and 2 levels were performed and their term values were analyzed with multichannel quantum defect theory. We have observed 6pnp(1/2,1/2${)}_{0}$ (28\ensuremath{\le}n\ensuremath{\le}50), 6p7p(3/2,3/2${)}_{0}$, 6pnp(1/2,3/2${)}_{1}$ (14\ensuremath{\le}n\ensuremath{\le}27), 6pnp(1/2,3/2${)}_{2}$ (42\ensuremath{\le}n\ensuremath{\le}54), and 6pnf 1/2[5/2${]}_{2}$ (28\ensuremath{\le}n\ensuremath{\le}51). Fitting multichannel quantum defect theory (MQDT) parameters to minimize deviation between the observed and theoretical energy values, we determined quantum defects ${\mathrm{\ensuremath{\mu}}}_{\mathrm{\ensuremath{\alpha}}}$ and unitary matrix elements ${\mathit{U}}_{\mathit{i}\mathrm{\ensuremath{\alpha}}}$ for J=0, 1, and 2 even-parity levels. Calculating theoretical energy values and determining their assignment with MQDT, we assigned observed levels and predicted unobserved levels and perturbers. Admixture coefficients for perturbing levels of J=0, 1, and 2 were calculated in order to ensure their assignments. \textcopyright{} 1996 The American Physical Society.