New spectroscopic data on high-lying excited even-parity levels of atomic neodymium

Highlights: • High-lying excited levels of Nd I are obtained by using RIMS. • 417 High-lying even-parity levels are revealed. • 172 energy levels are assigned unique J values. • The absolute accuracy is estimated to be better than ±0.2 cm⁻¹. The two-color three-photon photoionization technique was used to obtain information on high-lying excited even-parity levels of atomic neodymium in the 32,100–35,300 cm⁻¹ energy region. 417 even-parity levels, most of which were reported for the first time, were revealed. Out of these, 172 levels were assigned unique J values based on the J-momentum selection rule. The absolute accuracy of these levels was estimated to be better than ±0.2 cm⁻¹.