The Second Spark Spectrum of Lead Pb III

Abstract

Some additional multiplets arising from combinations between triplet terms of Pb III have been found. These are $6^{3}P_{0,1,2}\ensuremath{-}8^{3}S_{1}$, $6^{3}P_{0,1,2}\ensuremath{-}7^{3}D_{1,2,3}$, $7^{3}P_{0,1,2}\ensuremath{-}7^{3}D_{1,2,3}$ and $6^{3}P_{0,1,2}\ensuremath{-}pp^{3}P_{1}$. Twenty-one lines arising from combinations between singlet terms and intercombinations between singlet and triplet terms have been identified. Of particular interest is the $\mathrm{pp}^{1}D_{2}$ term which is found in combination with $6^{3}P_{1,2}$, $6^{1}P_{1}$, $6^{3}F_{2,3}$ and $6^{1}F_{3}$. Seven newly found lines of Tl II are also given, which correspond to some of the Pb III combinations classified in this paper.