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Two-Photon Detachment Of The Negative Chlorine Ion, Tsin-Fu Jiang, Anthony F. Starace
Two-Photon Detachment Of The Negative Chlorine Ion, Tsin-Fu Jiang, Anthony F. Starace
Anthony F. Starace Publications
Theoretical calculations of the two-photon detachment cross section of the negative chlorine ion are presented in the energy region from threshold to the single-photon ionization threshold using a transition-matrix method. Detailed analyses are presented of the effects of various kinds of electron correlations, whose net effect is a reduction of the uncorrelated Hartree-Fock model cross sections by up to 30%. Our cross sections have a much flatter variation with energy and a much lower magnitude (by up to a factor of 2 or 3) than the frozen-core free-electron results of M. Crance [J. Phys. B 20, 6553 (1987)] or the …
Variational Calculation Of Multiphoton Ionization Processes For The H Atom, Bo Gao, Anthony F. Starace
Variational Calculation Of Multiphoton Ionization Processes For The H Atom, Bo Gao, Anthony F. Starace
Anthony F. Starace Publications
Well-known variational principles for second-order perturbation matrix elements are extended to higher-order multiphoton processes for atomic hydrogen. Numerical applications to two- and three-photon ionization of the hydrogen ground state provide results comparable to those of analytic calculations, even near intermedaite-state resonances, yet without the complications involved in summation over intermediate states. Extensions to multiphoton processes for many-electron atoms are discussed briefly.
Hyperspherical Description Of Two-Electron Systems, Anthony F. Starace
Hyperspherical Description Of Two-Electron Systems, Anthony F. Starace
Anthony F. Starace Publications
While the use of hyperspherical coordinates to describe two-electron systems is quite old, it was Macek's introduction of a quasi-separable approximation in hyperspherical coordinates which made possible a host of theoretical studies elucidating the symmetries of doubly-excited states and the dynamics of processes involving two-electron atoms and ions. This work, up to about mid-1982, has been reviewed by Fano. However, much additional progress has been made since 1982, particularly on the symmetries of doubly excited electronic states, on the correspondences with molecular descriptions of two-electron systems, on the limitations of the quasi-separable approximation at small and at large distances, and …
The Calculation Of Photoionization Cross Sections, Anthony F. Starace
The Calculation Of Photoionization Cross Sections, Anthony F. Starace
Anthony F. Starace Publications
Photoionization is a sensitive probe of many-body and spin-dependent interactions. One can test our understanding of these interactions and the role they play in atomic dynamics by comparing the results of theoretical calculations with corresponding experimental measurements. One finds from such comparisons that our understanding of the photoionization process in atoms is excellent in many cases, imperfect in many others, and inadequate in still others. One finds in general also that the kinds of many-body and spin-dependent interactions included in a calculation is, in many cases, a more important consideration than the particular calculational method employed. In this brief report …