The Arc and Spark Spectra of Gadolinium

Abstract

Analyses based on wave-numbers and intensities have led to the classification of 1177 lines of Gd ii, and 1217 of Gd i. The percentages of the stronger lines which have been classified are respectively 77 and 90; of all lines 45 and 40. Almost all lines of astrophysical interest are included.All the identifiable terms are derived from the ground-state 8S° of the triply ionized atom. A complete analysis will probably be very difficult. The multiplets are remarkably regular for so high an atomic number. Intercombinations are numerous and strong, and often occur between terms differing widely in multiplicity and type. Terms of multiplicity 11 are present in Gd i and account for some of the strongest lines.