Spectrum and energy levels of the high-lying singly excited configurations of Nd III
Abstract
Fourier transform spectra of Nd Penning and hollow cathode discharge lamps were recorded within the region 32,500-54,000 cm-1 (3077-1852 ) and grating spectra of Nd vacuum sliding sparks were recorded within the regions 820-1159 and 1600-3250 . New energy levels were found using the observed wavelengths measured accurate to a few parts in 108 in Fourier transform spectra and to a few parts in 107 in grating spectra. Atomic structure and transition probability calculations of Nd III were made using the Cowan codes by adjusting energy parameters to fit all known Nd III levels. Nd-rich stellar spectra were also used to evaluate the new calculations. In total, 355 transitions were classified from observed spectra involving 116 previously experimentally unknown energy levels of the 4f37s, 4f36d, and 4f35f configurations of Nd III, all reported here for the first time. One newly identified level of the 4f35d configuration is also reported. Typical level energy uncertainties are 0.01 cm-1 for the 4f37s and 4f36d levels and 0.3 cm-1 for the 4f35f levels. In addition, calculated energy levels up to 130,936 cm-1 are presented, including eigenvector composition and calculated level lifetimes. Calculated transition probabilities and wavelengths between 1900-50,000 are also presented. Using newly established levels of the 4f37s configuration and the recently established levels of the 4f36s configuration, the ionisation energy of Nd III was estimated at 178,090330 cm-1, doubling the accuracy of the previously published value.
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.