Changes in Mean Square Nuclear Charge Radii of Nd II from Optical Isotope Shifts by Collinear Fast-Ion-Beam Laser Spectroscopy

High-resolution collinear fast-ion-beam-laser spectroscopy has been applied to investigate the optical isotope shifts for transition 4f⁴5d⁶K_11/2-(24445)°_11/2 of Nd II. From the measured optical isotope shifts, changes in mean-square nuclear charge radii δ(r²) (fm²) among five even-even neodymium isotopes have been deduced: (142,144) 0.282, (144, 146) 0.242, (146, 148) 0.274, (148, 150) 0.404. The results are in good agreement with experimental data from electronic x-ray spectroscopy and combined optical and x-ray spectroscopy.