Abstract
The structure of about 40 low-energy levels of singly ionized thulium is given. The twenty 4f12(3H6)5d6s levels are interpreted in JIJII and JILII coupling schemes, and the twelve 4f12(3H6)6s6p and six of the 4f136p levels are given JIJII designations. The first three levels of 4f126s2 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:

This publication has 4 references indexed in Scilit: