Excitation of doublet D-levels of a lutetium atom by electron impact

Abstract

The electron impact excitation of doublet D levels of the lutetium atom is studied by the method of extended crossing beams. At the exciting electron energy of 50 eV, 64 excitation cross sections are mea sured. In the electron energy range of 0-250 eV, nine excitation optical functions are recorded. The occur rence of perturbations in the spectral series 6s 2 ( 1 S)6p -6s 2 ( 1 S)nd 2 D 3/2 is discussed.

Excitation of doublet F-levels of a lutetium atom by electron impact

“…Seventy-seven excitation crosssections have been measured for spectral lines occurring as a result of doublet F levels populated in electron collisions with lutetium atoms. Unlike [10] where excitation of even D levels was the dominant pattern, only a single transition at λ = 543.788 nm from the even level 5d 2 ( 3 F)6s 2 F5/2 (E = 25860 cm -1 ) was identified in our study while all other transitions studied took place as a result of excitation of odd levels. The dependence of excitation cross sections on the exciting electron energy (optical excitation functions, OEFs) has been recorded for transitions originating at nine upper levels within the electron energy range of 0 to 250 eV.…”

“…These changes are also reflected in the compilation [8] and taken into consideration in Tables 1, 2 of the present work. Besides, similar to the case with D levels of LuI [10], a great number of lines lying in the visible part of the spectrum could not be found in any preceding publications. We have endeavored to classify these lines showing that they arise as a result of transitions from higher-lying levels to levels of non-resonance terms with energies lying within the range E = 18851-30183 cm -1 ; the corresponding [8], [13].…”

“…[7,11]). In particular this relationship was studied for the excited 2 D series of the lutetium atom [10]. The sequence 6s 2 nf 2 F°5/2 is shown in [1] to become perturbed around n = 16 (after correcting n per [13]) while the sequence 6s 2 nf 2 F°7/2 appears to be free of major perturbations.…”

“…Almost all transitions investigated terminated at levels of the ground term, 5d( 2 D)6s 2 2 D. As the experiment took place before newly-designed equipment and new methodology were tested, its results should be deemed as preliminary. An improved method was used later to study excitation of doublet D levels of the lutetium atom [10], with even levels making up a significant majority. This paper reports findings from a study of excitation of doublet F levels of the lutetium atom.…”

“…This paper reports findings from a study of excitation of doublet F levels of the lutetium atom. Considering that the experiment, similarly to [5,10], is based on the method of extended crossing beams which is given detailed treatment in a number of publications (e.g., [6,11]), a description of the equipment and methodology foundations would be unnecessary here. We will only make note of several main conditions pertinent to the lutetium experiment proper.…”