Hyperfine structure measurements of Nb I and Nb II by Fourier transform spectroscopy

• Published in: Journal of quantitative spectroscopy & radiative transfer 2021-12, Vol.276, p.107955, Article 107955
• Main Authors: Geng, Yidan, Jiao, Congcong, Yang, Zhihu, Gong, Yimin, Dai, Zhenwen
• Format: Article
• Language: English
• Subjects: Fourier transform spectroscopy; Hyperfine structure; Niobium
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/j.jqsrt.2021.107955

•Fourier transform (FT) spectra were used to extend the study of the hyperfine structure (HFS) of Nb I And Nb II energy levels.•HFS constants A for 68 levels of Nb I from 11,524.65 to 45,719.07 cm−1 were determined, of which 26 results are reported for the first time, as far as we know. Our study increased the total number of HFS constants A to 349 Nb I levels.•HFS constants A for 57 levels of Nb II from 2356.816 to 73,869.773 cm−1 were determined, of which 46 results are reported for the first time, as far as we know. Our study increased the total number of HFS constants A to 99 Nb II levels. Some of the archival data derived from the Fourier transform spectrometer (FTS) at the US National Solar Observatory ranging from 0 − 36,947 cm−1 were investigated to study the hyperfine structure (HFS) patterns of Nb I and Nb II lines. The analysis of 155 lines in the FTS spectra was performed by a least squares fitting to derive values of the magnetic dipole HFS constant A. In total, the HFS constant A was determined for 68 levels of Nb I between 11,524.65 and 45,719.07 cm−1 and for 57 levels of Nb II between 2356.816 and 73,869.773 cm−1. 26 results for Nb I and 46 results for Nb II are reported for the first time, as far as we know.