E. P. Vidolova-Angelova, E. P. Ivanova, and L. N. Ivanov, "Energies and autoionization widths of low-lying resonances of ytterbium atoms," Opt. Spectrosc. USSR 50, 243–250 (1981).

G. I. Bekov *et al*., "Multistep laser spectroscopy of high-lying triplet states of ytterbium atoms," Opt. Spectros. USSR 48, 435–439 (1980).

P. Camus, A. Debarre, and C. Morillon, "Highly excited levels of neutral ytterbium I. Two-photon and two-step spectroscopy of even spectra," J. Phys. B 13, 1073–1987 (1980).

J. J. Wynne and J. A. Armstrong, "Systematic behavior in alkaline earth spectra: A multichannel quantum defect analysis," IBM J. Res. Dev. 23, 490–503 (1979).

L. N. Ivanov and L. I. Podobedova, "Formally exact perturbation theory with a model potential as a zeroth approximation I. Transition energies in Fe ions including effects of inner-shell electrons," J. Phys. B. 10, 1001–1013 (1977).

R. F. Stebbings *et al*., "Studies of xenon atoms in high Rydberg states,"Phys. Rev. A12, 1453–1458 (1975); S. Liberman and J. Pinard, "Experimental studies of high-lying Rydberg states in atomic rubidium," Phys. Rev. A20, 507–518 (1979).

L. N. Ivanov and V. S. Letokhov, "Selective ionization of atoms by light and electric field," Quantum Electron. USSR 2, 585–590 (1975); R. V. Ambartzumjan *et al*., "Dye-laser-excitation of high-lying states of sodium atoms and autoionization by electric field," JETP Lett. 21, 595–598 (1975).

K. T. Lu, "Quantum-defect analysis of the effects of *np*^{2} terms on the singlet terms of alkaline earths and of their isoelectronics sequences," J. Opt. Soc. Aim. 64, 706–711 (1974).

C. M. Lee, "Spectroscopy and collision theory III. Atomic eigenchannel calculation by a Hartree-Fock-Roothaan method," Phys. Rev. A 10, 584–600 (1974).

K. T. Lu, "Spectroscopy and collision theory. The Xe absorption spectrum," Phys. Rev. A 4, 579–596 (1971).

U. Fano, "Quantum defect theory of 1 uncoupling in H_{2} as an example of channel-interaction treatment," Phys. Rev. A 2, 353–365 (1970).

J. J. Wynne and J. A. Armstrong, "Systematic behavior in alkaline earth spectra: A multichannel quantum defect analysis," IBM J. Res. Dev. 23, 490–503 (1979).

G. I. Bekov *et al*., "Multistep laser spectroscopy of high-lying triplet states of ytterbium atoms," Opt. Spectros. USSR 48, 435–439 (1980).

P. Camus, A. Debarre, and C. Morillon, "Highly excited levels of neutral ytterbium I. Two-photon and two-step spectroscopy of even spectra," J. Phys. B 13, 1073–1987 (1980).

P. Camus, A. Debarre, and C. Morillon, "Highly excited levels of neutral ytterbium I. Two-photon and two-step spectroscopy of even spectra," J. Phys. B 13, 1073–1987 (1980).

U. Fano, "Quantum defect theory of 1 uncoupling in H_{2} as an example of channel-interaction treatment," Phys. Rev. A 2, 353–365 (1970).

W. C. Martin, R. Zalubas, and L. Hagan, Atomic Energy Levels. The Rare-Earth Elements (National Bureau of Standards, Washington, D.C., 1978).

E. P. Vidolova-Angelova, E. P. Ivanova, and L. N. Ivanov, "Energies and autoionization widths of low-lying resonances of ytterbium atoms," Opt. Spectrosc. USSR 50, 243–250 (1981).

L. N. Ivanov and L. I. Podobedova, "Formally exact perturbation theory with a model potential as a zeroth approximation I. Transition energies in Fe ions including effects of inner-shell electrons," J. Phys. B. 10, 1001–1013 (1977).

L. N. Ivanov and V. S. Letokhov, "Selective ionization of atoms by light and electric field," Quantum Electron. USSR 2, 585–590 (1975); R. V. Ambartzumjan *et al*., "Dye-laser-excitation of high-lying states of sodium atoms and autoionization by electric field," JETP Lett. 21, 595–598 (1975).

E. P. Vidolova-Angelova, E. P. Ivanova, and L. N. Ivanov, "Energies and autoionization widths of low-lying resonances of ytterbium atoms," Opt. Spectrosc. USSR 50, 243–250 (1981).

C. M. Lee, "Spectroscopy and collision theory III. Atomic eigenchannel calculation by a Hartree-Fock-Roothaan method," Phys. Rev. A 10, 584–600 (1974).

L. N. Ivanov and V. S. Letokhov, "Selective ionization of atoms by light and electric field," Quantum Electron. USSR 2, 585–590 (1975); R. V. Ambartzumjan *et al*., "Dye-laser-excitation of high-lying states of sodium atoms and autoionization by electric field," JETP Lett. 21, 595–598 (1975).

K. T. Lu, "Quantum-defect analysis of the effects of *np*^{2} terms on the singlet terms of alkaline earths and of their isoelectronics sequences," J. Opt. Soc. Aim. 64, 706–711 (1974).

K. T. Lu, "Spectroscopy and collision theory. The Xe absorption spectrum," Phys. Rev. A 4, 579–596 (1971).

W. C. Martin, R. Zalubas, and L. Hagan, Atomic Energy Levels. The Rare-Earth Elements (National Bureau of Standards, Washington, D.C., 1978).

P. Camus, A. Debarre, and C. Morillon, "Highly excited levels of neutral ytterbium I. Two-photon and two-step spectroscopy of even spectra," J. Phys. B 13, 1073–1987 (1980).

L. N. Ivanov and L. I. Podobedova, "Formally exact perturbation theory with a model potential as a zeroth approximation I. Transition energies in Fe ions including effects of inner-shell electrons," J. Phys. B. 10, 1001–1013 (1977).

R. F. Stebbings *et al*., "Studies of xenon atoms in high Rydberg states,"Phys. Rev. A12, 1453–1458 (1975); S. Liberman and J. Pinard, "Experimental studies of high-lying Rydberg states in atomic rubidium," Phys. Rev. A20, 507–518 (1979).

E. P. Vidolova-Angelova, E. P. Ivanova, and L. N. Ivanov, "Energies and autoionization widths of low-lying resonances of ytterbium atoms," Opt. Spectrosc. USSR 50, 243–250 (1981).

J. J. Wynne and J. A. Armstrong, "Systematic behavior in alkaline earth spectra: A multichannel quantum defect analysis," IBM J. Res. Dev. 23, 490–503 (1979).

W. C. Martin, R. Zalubas, and L. Hagan, Atomic Energy Levels. The Rare-Earth Elements (National Bureau of Standards, Washington, D.C., 1978).

J. J. Wynne and J. A. Armstrong, "Systematic behavior in alkaline earth spectra: A multichannel quantum defect analysis," IBM J. Res. Dev. 23, 490–503 (1979).

K. T. Lu, "Quantum-defect analysis of the effects of *np*^{2} terms on the singlet terms of alkaline earths and of their isoelectronics sequences," J. Opt. Soc. Aim. 64, 706–711 (1974).

P. Camus, A. Debarre, and C. Morillon, "Highly excited levels of neutral ytterbium I. Two-photon and two-step spectroscopy of even spectra," J. Phys. B 13, 1073–1987 (1980).

L. N. Ivanov and L. I. Podobedova, "Formally exact perturbation theory with a model potential as a zeroth approximation I. Transition energies in Fe ions including effects of inner-shell electrons," J. Phys. B. 10, 1001–1013 (1977).

G. I. Bekov *et al*., "Multistep laser spectroscopy of high-lying triplet states of ytterbium atoms," Opt. Spectros. USSR 48, 435–439 (1980).

E. P. Vidolova-Angelova, E. P. Ivanova, and L. N. Ivanov, "Energies and autoionization widths of low-lying resonances of ytterbium atoms," Opt. Spectrosc. USSR 50, 243–250 (1981).

R. F. Stebbings *et al*., "Studies of xenon atoms in high Rydberg states,"Phys. Rev. A12, 1453–1458 (1975); S. Liberman and J. Pinard, "Experimental studies of high-lying Rydberg states in atomic rubidium," Phys. Rev. A20, 507–518 (1979).

U. Fano, "Quantum defect theory of 1 uncoupling in H_{2} as an example of channel-interaction treatment," Phys. Rev. A 2, 353–365 (1970).

K. T. Lu, "Spectroscopy and collision theory. The Xe absorption spectrum," Phys. Rev. A 4, 579–596 (1971).

C. M. Lee, "Spectroscopy and collision theory III. Atomic eigenchannel calculation by a Hartree-Fock-Roothaan method," Phys. Rev. A 10, 584–600 (1974).

L. N. Ivanov and V. S. Letokhov, "Selective ionization of atoms by light and electric field," Quantum Electron. USSR 2, 585–590 (1975); R. V. Ambartzumjan *et al*., "Dye-laser-excitation of high-lying states of sodium atoms and autoionization by electric field," JETP Lett. 21, 595–598 (1975).

W. C. Martin, R. Zalubas, and L. Hagan, Atomic Energy Levels. The Rare-Earth Elements (National Bureau of Standards, Washington, D.C., 1978).