3dnd J = 4, 5 autoionizing levels in Ca: laser optogalovanic spectroscopy and theoretical analysis (Journal article)
Assimopoulos, S./ Bolovinos, A./ Luc-Koenig, E./ Cohen, S./ Lyras, A./ Tsekeris, P./ Aymar, M.
We report the even parity J = 4,5 autoionizing spectra of calcium below the 3d threshold, investigated by two-step laser excitation from the 3d4s metastables through the 3d4p F-3(3, 4), F-1(3) intermediate states and subsequent optogalvanic detection. The 3d4s states are populated by electronic collisions in a d.c. glow discharge sustained in a Ca heat-pipe. More than a hundred resonant transitions have been measured with an accuracy of similar to 0.2 cm(-1) for the narrow ones using standard laser calibration techniques. The high lying levels are assigned to all expected 3dnd J = 4, 5 autoionizing series. Moreover, some 3dng J = 4, 5 levels are observed. The theoretical interpretation is achieved by a combination of the nearly ab initio eigenchannel R-matrix and multichannel quantum-defect (MQDT) methods as well as by an empirical determination of the MQDT parameters in the phase-shifted formulation. Theoretical energy level positions and excitation profiles are compared with the experimental data confirming the identification of the observed structures. Strong mixing between 3dnd J = 4 series is found, while the 3dng ones do not couple with the 3dnd series. Further insight into the strong channel mixing in the studied energy range is provided by a comprehensive review of the excitation profiles in the vicinity of the 4p5p D-3(3) perturber as obtained from a number of intermediate levels used in the present and in earlier experiments. Systematic electron correlation trends for Ndnd J = 4 series of Ca(N = 3), Sr(N = 4) and Ba(N = 5) are discussed.
|Institution and School/Department of submitter:||Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών και Τεχνολογιών. Τμήμα Βιολογικών Εφαρμογών και Τεχνολογιών|
|Keywords:||quantum-defect theory,r-matrix calculation,optogalvanic spectroscopy,neutral barium,spectrum,calcium,series,states,limit|
|Link:||<Go to ISI>://000073581700004|
|Appears in Collections:||Άρθρα σε επιστημονικά περιοδικά ( Ανοικτά)|
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|Assimopoulos-1998-3dnd J = 4, 5 autoio.pdf||462.78 kB||Adobe PDF||View/Open Request a copy|
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