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Full-Text Articles in Physics
New Perspectives On Electron Correlations, Anthony F. Starace
New Perspectives On Electron Correlations, Anthony F. Starace
Anthony F. Starace Publications
Two formulations for describing electronic excitations developed by Fano and his school are reviewed. The transition matrix formulation of atomic photoionization has provided new perspectives on the well-known random phase approximation and on its relation to configuration interaction. The hyperspherical coordinate approach to two electron states and collision processes has provided new perspectives on the classification of two-electron excitation channels and on the evolution of highly excited electronic states.
Book Review: The Theory Of Atomic Structure And Spectra By Robert D. Cowan, Anthony F. Starace
Book Review: The Theory Of Atomic Structure And Spectra By Robert D. Cowan, Anthony F. Starace
Anthony F. Starace Publications
The field of atomic spectroscopy is currently experiencing a resurgence of interest owing on the one hand to its applications in astrophysics, plasma physics, and other fields and on the other hand to the development of new experimental tools to probe atomic structures. One example of the latter is the use of tunable lasers to study highly excited atoms in the presence of strong external electric and magnetic fields. Another is the use of synchrotron radiation to probe with increasing detail the inner shell structure of rare earth, actinide, and other heavy atoms.
Photoelectron Angular Distributions: Energy Dependence For S Subshells, Steven T. Manson, Anthony F. Starace
Photoelectron Angular Distributions: Energy Dependence For S Subshells, Steven T. Manson, Anthony F. Starace
Anthony F. Starace Publications
An overview of the theory of photoelectron angular distributions for atoms is presented. Its features, which are embodied in a single asymmetry parameter β in the electric dipole approximation, are examined within the framework of the angular momentum transfer formulation. The β parameter is in principle always energy dependent. Within the LS coupling approximation, however, there are instances, each representing a multitude of particular photoionization processes, in which β is an analytically determined constant. The energy dependence of the β parameters in such instances is due entirely to spin-orbit and other relativistic interactions. The study of the energy dependence of …
Random-Phase Approximation To One-Body Transition Matrix Elements For Open-Shell Atoms, Anthony F. Starace, Siamak Shahabi
Random-Phase Approximation To One-Body Transition Matrix Elements For Open-Shell Atoms, Anthony F. Starace, Siamak Shahabi
Anthony F. Starace Publications
A graphical procedure is presented for evaluating each term in the equation satisfied by the first-order transition matrix for an arbitrary (open-shell) atom. For those terms involving the interaction of excited virtual pairs of electrons with the ionic core, we introduce the approximation that there is no exchange of orbital or spin angular momentum with the ionic core. This approximation is shown to lead to the random-phase approximation (RPA) equations in the closed-shell-atom case; we use it to define the RPA for open-shell atoms. The single equation satisfied by the first-order transition matrix is used to obtain a set of …
Review Of Atoms And Molecules By M. Weissbluth, Anthony F. Starace
Review Of Atoms And Molecules By M. Weissbluth, Anthony F. Starace
Anthony F. Starace Publications
The advent of high-powered lasers and of dedicated synchrotron light sources and the needs of research in such areas as astrophysics and fusion have led to a resurgence of interest in atomic and molecular physics. Concurrently, there have been significant advances in atomic and molecular theory, not only in the ability to make more reliable numerical predictions but also in the detailed understanding of the dynamics of atomic and molecular collisions. The nonspecialist or beginning graduate student who must read the scientific journals to learn of these advances often finds that the requisite basic knowledge is extensive. Mitchel Weissbluth, whose …
Polarization Of Fluorescence Radiation Subsequent To Inner-Shell Photoionization: Ls-Coupling Formulas, Anthony F. Starace
Polarization Of Fluorescence Radiation Subsequent To Inner-Shell Photoionization: Ls-Coupling Formulas, Anthony F. Starace
Anthony F. Starace Publications
The polarization and angular distribution of fluorescence radiation subsequent to inner-shell photoionization in atoms are presented here in the important special case that dynamic amplitudes are calculated in LS coupling taking full account of anisotropic electron-ion interactions. The resulting formulas require for their evaluation no more dynamical information than is usually obtained in an LS-coupling calculation of the photoionization cross section. Exact geometrical relationships which are obscured in more general treatments become apparent in an LS-coupling formulation. Thus it is shown that in LS coupling the fluorescence resulting from photoionization of an s subshell in an atom having …