The early work on arc spectra of curium resulted in wavelengths for about 200 lines and 244 Cm - 242 Cm isotope shifts for most of these lines (51.1; 56.1). Wavelengths, intensities and classifications of 2034 lines of Cm I and Cm II emitted by an electrodeless discharge tube were selected from a total of 13260 lines and published in (76.1). By varying the excitation conditions of the tube, 30 % of these lines were assigned to Cm II, whereas 19 % of the lines had an undetermined Cm I or Cm II assignment. These observations were made in the region 240-910 nm on the Paschen-Runge spectrograph at the Argonne National Laboratory and were extended in the near infrared by using a 3.4 Ebert spectrograph. The wavelength range 840-2450 nm was recorded by Fourier transform spectrometry at Laboratoire Aimé Cotton with the same light sources and 1734 infrared lines were measured with an accuracy of 0.005 cm-1 (76.12).
Until 1986, the advances in the Cm II analysis was only mentionned in conference abstracts (67.4; 67.6; 81.3). Two dozens of levels of 5f87s were interpreted in a survey of 5fN7s configurations by the Slater-Condon method (80.4). At present, more than 4100 Cm II lines are classified as transitions between 432 odd levels and 162 even levels (86.2), with the support of Zeeman effect and isotope shift measurements. The accuracy of the g-values ranges from 0.003 to 0.02 Lorentz unit depending on the resolution of the Zeeman pattern. Isotope shifts have been measured for more than 6000 lines of Cm I and Cm II with isotopically different samples of 244Cm, 245Cm, 246Cm and 248Cm (80.3). By assigning an arbitrary zero shift to the ground level 5f77s2 8S7/2, and by using eventually a relative isotope shift factor, these values were converted into 246 Cm - 244 Cm level shifts for all but five levels. Ninety-four levels are assigned to 4 odd configurations and one hundred levels to 4 even configurations, 5f9 being the only missing configuration predicted below 50000 cm-1 (71.2). The extended isotope shift measurements led to revise some assignments of upper 5f87s levels given in (80.4).
Parallel researches have been led at the I.V. Kurchatov Institute, Moscow and have resulted in a wavelength list of 6774 lines (79.5) and isotope shifts for 97 lines (79.4).