The third spectrum of bismuth (Bi III) with its ground configuration 5d¹⁰6s²6p has been investigated in the wavelength region 278–2000 Å using spectrograms recorded on a 3-m normal incidence vacuum spectrograph. The observed spectrum was interpreted using semi-empirical calculations with Cowan's code in the framework of the quasi-Relativistic Hartree-Fock method. Analyses made by previous investigators on one and three-electron systems were checked thoroughly, while the tentative identification of the ²S_1/2 level of the 5d¹⁰6s6p² configuration is confirmed. For the first time we had investigated the 6p³, 6s6p6d and 6s6p7s odd configurations based on the identification of 99 spectral lines. In total, 67 energy levels are now established in the 5d¹⁰[6s²np (n = 6–8) + 6s²nf (n = 5–7) + 6s²nh (n = 6–7)], 6s6p² and 5d⁹6s²6p² configurations, among which 23 energy levels were newly located. The least squares parametric fitting calculations were performed to interpret the final results of the analysis. Optimization of the observed energy levels was carried out with the computer program LOPT. The ionization energy was found to be 206,242.0 ± 1.4 cm⁻¹ (25.5708±0.0002 eV).

使用在3-m垂直入射真空光谱仪上记录的光谱图，研究了地平面为5d ¹⁰ 6s ² 6p的铋的第三光谱（Bi III）。在准相对论性Hartree-Fock方法的框架内，使用Cowan的代码使用半经验计算来解释观测到的光谱。彻底检查了先前研究人员对一电子系统和三电子系统的分析，同时确认了5d ¹⁰ 6s6p ²构型的² S _1/2水平的初步鉴定。我们第一次调查了6p ³，6s6p6d和6s6p7s的奇数配置基于对99条谱线的识别。总共在5d ^10中建立了67个能级[6s ² n p（n  = 6-8）+ 6s ² n f（n  = 5-7）+ 6s ² n h（n  = 6-7）] ，6s6p ²和5d ⁹ 6s ² 6p ²配置，其中新定位了23个能级。进行最小二乘参数拟合计算以解释分析的最终结果。使用计算机程序LOPT对观察到的能量水平进行优化。发现电离能为206,242.0± 1.4cm ^-1（25.5708±0.0002eV）。