High-resolution grating and Fourier transform spectroscopy measurements, using hollow-cathode and electrodeless discharge lamp sources, have resulted in a list of 92000 lines of U I and U II. The wave-number accuracy is about 0.003 cm−1. With this list and new Zeeman structure, isotope-shift, and 233U hyperfine-structure spectrograms, we have found 500 new U I levels. We now know 1240 even levels between 7020 and 42000 cm−1 and 360 odd levels up to 38000 cm−1. All levels expected to lie below 10000 cm−1 have been found. Levels of five odd configurations (ƒ3ds2, ƒ3d2s, ƒ4sp, ƒ3ds8s, ƒ4dp) and seven even configurations (ƒ4s2, ƒ2d2s2, ƒ3s2p, ƒ3dsp, ƒ4ds, ƒ3d2p, ƒ3ds8p) are now known.
© 1976 Optical Society of America
Jean Blaise and Leon J. Radziemski, Jr., "Energy levels of neutral atomic uranium (U I)," J. Opt. Soc. Am. 66, 644-659 (1976)