The structure of about 40 low-energy levels of singly ionized thulium is given. The twenty 4ƒ12(3H6)5d6s levels are interpreted in JIJII and JILII, coupling schemes, and the twelve 4ƒ12(3H6)6s6p and six of the 4ƒ136p levels are given JIJII designations. The first three levels of 4ƒ126s2 are established. The intensity relations of the transitions connecting some of the levels are discussed. The following values for the interaction parameters are obtained directly from these levels: ζƒ=2506 cm-1 ζd=1213 cm-1 ζp=2111 cm-1 (from 4ƒ136p) ζp=3467 cm-1 (from 4ƒ126s6p) Gƒs= 212 cm-1Gds=1535 cm-1Gps=2613 cm-1 More than 200 lines are classified.
NISSAN SPECTOR, "Level Structure of Singly Ionized Thulium (Tm II)," J. Opt. Soc. Am. 57, 312-317 (1967)