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Joseph Macek

Bio: Joseph Macek is an academic researcher from University of Nebraska–Lincoln. The author has contributed to research in topics: Born approximation & Wave function. The author has an hindex of 16, co-authored 39 publications receiving 1709 citations.

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Journal ArticleDOI
TL;DR: In this paper, a new formulation for the angular distribution and the polarization of light excited by atomic and electronic collisions and modulated in time by the action of internal and external fields is presented.
Abstract: A new formulation is presented for the angular distribution and the polarization of light excited by atomic and electronic collisions and modulated in time by the action of internal and external fields. The formulation disentangles geometrical and dynamical effects and stresses the extraction of data on the alignment and orientation of radiating atoms from observations of the emitted light. The treatment is set in the context of recent experimental and theoretical literature and points to new avenues of research.

696 citations

Journal ArticleDOI
TL;DR: In this paper, the first term in the Neuman expansion of Faddeev's equation for the final state of the electron-proton-residual ion system was calculated.
Abstract: The cross section for ejecting electrons by 300-keV protons is calculated using the first term in the Neuman expansion of Faddeev's equation for the final state of the electron-proton-residual ion system. This approximation predicts a peak at 0\ifmmode^\circ\else\textdegree\fi{} in the angular distribution of electrons ejected with a velocity approximately equal to the velocity of outgoing protons. Numerical results for He and ${\mathrm{H}}_{2}$ target gases are given and compared with the experiments of Rudd and co-workers. The qualitative behavior of the forward peak in the experimental angular distributions is well accounted for.

203 citations

Journal ArticleDOI
TL;DR: In this paper, the theory of measurements in which photons are detected in delayed coincidence with a scattered particle is developed in a form specifically applicable to atomic collisions, and equations which relate the measured coincidence rate to excitation amplitudes are obtained.
Abstract: The theory of measurements in which photons are detected in delayed coincidence with a scattered particle is developed in a form specifically applicable to atomic collisions. Equations are obtained which relate the measured coincidence rate to excitation amplitudes. These equations incorporate the polarization of the radiation, the fine and hyperfine structure of the atomic levels, the coherence of the radiation, and the time dependence of the radiation intensity. A semiclassical model for certain transitions is introduced to illustrate new features of coincidence measurements. The $\mathrm{Ly}\ensuremath{-}\ensuremath{\alpha}$ transitions in hydrogen and $^{1}P\ensuremath{\rightarrow}^{1}S$ transitions in He are treated in detail to illustrate the general theory.

167 citations

Journal ArticleDOI
TL;DR: In this article, a peaking-approximation cross section for electron capture from a hydrogen-like ion of large nuclear charge Z/sub T/e/sup 2/ by a bare ion of charge moving with speed v.
Abstract: We have systematically developed a new approximation for the calculation of the cross section for electron capture from a hydrogenlike ion of large nuclear charge Z/sub T/e/sup 2/ by a bare ion of charge Z/sub P/e/sup 2/ moving with speed v. The amplitude in the wave treatment is obtained through consistent expansion in the small parameters Z/sub P//Z/sub T/ and Z/sub P/e/sup 2//hv; however, the ratio Z/sub T/e/sup 2//hv is not assumed small. Following a careful analysis of the approach to the energy shell, an off-shell factor is seen to arise which does not appear in the impulse approximation. The effects of this factor on the capture amplitude are explored. Using a peaking approximation, we derive a closed-form expression for the 1s..-->..ns capture amplitude which includes the effects of the off-shell factor and is accurate to order (Z/sub P/e/sup 2//hv)/sup 2/. We tabulate the peaking-approximation cross section. The derivation of the asymptotic form of the cross section when Z/sub P//Z/sub T/<<1 is justified. Using a realistic one-electron model, K-shell capture cross sections are calculated for protons on carbon, neon, and argon. These are seen to represent the data generally better than do the impulse-approximation cross sections.

112 citations

Journal ArticleDOI
TL;DR: In this article, a simple correction factor in the limit of small ε-expansion was derived for highly asymmetric electron-capture collisions, where the ratio of the small charge to the large charge of the target is the natural expansion parameter.
Abstract: For highly asymmetric electron-capture collisions, the ratio of the small charge ${Z}_{P}$, here taken to be that of the projectile, to the large charge of the target ${Z}_{T}$ forms the natural expansion parameter. Previous treatments with use of $\frac{{Z}_{P}}{{Z}_{T}}$ expansions obtain the impulse approximation which is shown to err by unknowingly neglecting terms of order ${(\frac{{Z}_{T}}{v})}^{2}$; a simple correction factor in the limit of small $\frac{{Z}_{P}}{v}$ is derived.

70 citations


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Journal ArticleDOI
TL;DR: The current state of the art on post-Newtonian methods as applied to the dynamics and gravitational radiation of general matter sources (including the radiation reaction back onto the source) and inspiralling compact binaries is presented.
Abstract: The article reviews the current status of a theoretical approach to the problem of the emission of gravitational waves by isolated systems in the context of general relativity. Part A of the article deals with general post-Newtonian sources. The exterior field of the source is investigated by means of a combination of analytic post-Minkowskian and multipolar approximations. The physical observables in the far-zone of the source are described by a specific set of radiative multipole moments. By matching the exterior solution to the metric of the postNewtonian source in the near-zone we obtain the explicit expressions of the source multipole moments. The relationships between the radiative and source moments involve many nonlinear multipole interactions, among them those associated with the tails (and tails-of-tails) of gravitational waves. Part B of the article is devoted to the application to compact binary systems. We present the equations of binary motion, and the associated Lagrangian and Hamiltonian, at the third post-Newtonian (3PN) order beyond the Newtonian acceleration. The gravitational-wave energy flux, taking consistently into account the relativistic corrections in the binary moments as well as the various tail eects, is derived through 3.5PN order with respect to the quadrupole formalism. The binary’s orbital phase, whose prior knowledge is crucial for searching and analyzing the signals from inspiralling compact binaries, is deduced from an energy balance argument.

2,067 citations

Journal ArticleDOI
TL;DR: In this article, the Bethe theory has been updated with a number of new developments which need to be included in that body of material, such as the ${z}^{3}$ effect and the stopping power for particles at extreme relativistic energies.
Abstract: Since the appearance of the title paper, a number of new developments have occurred which need to be included in that body of material. We present additional remarks and clarifications which supplement and update numerous aspects of the Bethe theory discussed in the earlier paper. We also bring the bibliography up to date. Plasma stopping power, the ${z}^{3}$ effect, and stopping power for particles at extreme relativistic energies are among the new topics included. We make several comments on Fano's earlier review article, Ann. Rev. Nucl. Sci. 13, 1 (1963).

1,233 citations

Journal ArticleDOI
TL;DR: In this paper, a thorough treatment of universality for the system of three identical bosons is presented, and the universal information that is currently available for other 3-body systems is summarized.

968 citations

01 Jan 1972
TL;DR: In this paper, the Bethe theory has been updated with a number of new developments which need to be included in that body of material, such as the ${z}^{3}$ effect and the stopping power for particles at extreme relativistic energies.
Abstract: Since the appearance of the title paper, a number of new developments have occurred which need to be included in that body of material. We present additional remarks and clarifications which supplement and update numerous aspects of the Bethe theory discussed in the earlier paper. We also bring the bibliography up to date. Plasma stopping power, the ${z}^{3}$ effect, and stopping power for particles at extreme relativistic energies are among the new topics included. We make several comments on Fano's earlier review article, Ann. Rev. Nucl. Sci. 13, 1 (1963).

832 citations

Journal ArticleDOI
TL;DR: In this article, a detailed review of bound state properties of loosely bound nuclei is presented, with emphasis on genuine three-body features, and a number of plausible model interactions, including treatments of the Pauli principle, are presented.

723 citations