Optical isotopic analysis; Uranium; Laser ablation molecular isotopic spectrometry; Laser induced breakdown spectroscopy; Isotope shift;INDUCED BREAKDOWN SPECTROSCOPY; LEAST-SQUARES REGRESSION; EMISSION-SPECTROMETRY; QUANTITATIVE-ANALYSIS; ELECTRONIC-STRUCTURE; COMPUTER-SIMULATION; ENERGY-LEVELS; UO; FEMTOSECOND; RATIO

Through computer simulation on experimentally acquired optical spectra, uranium isotopic analysis by laser ablation molecular isotopic spectrometry and laserinduced breakdown spectroscopy were studied. The use of only one spectral feature, either the strong UO band at 593.55 nm or the nearby U I 593.382 nm line, are similar in precisions (similar to 1.5% in absolute U-235 abundances). Precision improves to 0.72% with the use of a group of U atomic lines from 591.6 to 596.5 nm. The use of both molecular bands and atomic lines further advances the precision to 0.42% and compares well with the U II 424.437 nm single-line benchmark (0.48% precision).