Notes. The first 3 columns are the configuration, term, and J value assignments for the level, parent terms of the 4f³ core electrons are in parentheses, any number following a term symbol is used to distinguish recurrent terms of equivalent electrons, and a° following a term symbol indicates a term of odd parity. The fourth column is the optimised energy and its associated uncertainty in parentheses in units represented by the final decimal place of the energy value, the fifth column lists the number of lines classified for each level in the Nd–Ar PDL FT spectra, the number in parentheses is the number of blended or weak lines omitted from the level energy optimisation. The sixth and seventh columns are the differences between observed and calculated values of the present work using the parameterised Cowan code and of Gaigalas et al. (2019), respectively. The remaining columns list the Landé 𝑔-factors and three leading eigenvector percentages calculated using the Cowan code in this work. The level energies are optimised using LOPT using all 579 classified transitions listed in Table 4. The full version of this table is available at the CDS.