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in subjects: "Excitation"

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Excitation of giant resonances via direct reactions

Experimental measurements of electric giant multipole resonances are discussed. The parameters of the giant quadrupole resonance are now firmly established by an extensive set of measurements. The GQR is providing a significant influence in other areas of nuclear physics. The monopole resonance has now been established and its observation has provided the first direct measure of the nuclear compressibility. A strong case for the existence of a giant octupole resonance is now being made through … more

Date: January 1, 1982

Creator: Bertrand, F.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A unified theory of resonant excitation of kinetic ballooning modes by energetic ions/alpha particles in tokamaks

A complete theory of wave-particle interactions is presented whereby both circulating and trapped energetic ions can destabilize kinetic ballooning modes in tokamaks. Four qualitatively different types of resonances, involving wave-precessional drift, wave-transit, wave-bounce, and precessional drift-bounce interactions, are identified, and the destabilization potential of each is assessed. For a characteristic slowing-down distribution function, the dominant interaction is that which taps thos… more

Date: October 1, 1991

Creator: Biglari, H. & Chen, L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Alignment and orientation in ion/endash/atom collisions

Recent progress in the theoretical study of alignment and orientation in atom-atom and ion-atom collisions at intermediate energies is reviewed. Recent systematic studies of the alignment and orientation of electronic charge cloud distributions of excited states resulting from such collisions clearly have provided more detailed information about the underlying collision dynamics. However, since accurate determination of these parameters is quite difficult, both theoretically and experimentally,… more

Date: January 1, 1987

Creator: Kimura, M. & Lane, N.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Selective population of high-j states via heavy-ion-induced transfer reactions

One of the early hopes of heavy-ion-induced transfer reactions was to populate states not seen easily or at all by other means. To date, however, I believe it is fair to say that spectroscopic studies of previously unknown states have had, at best, limited success. Despite the early demonstration of selectivity with cluster transfer to high-lying states in light nuclei, the study of heavy-ion-induced transfer reactions has emphasized the reaction mechanism. The value of using two of these react… more

Date: January 1, 1982

Creator: Bond, P.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Research in theoretical nuclear physics

The work done during the past year covers three separate areas, low energy nuclear reactions intermediate energy physics, and nuclear structure studies. This manuscript summarizes our achievements made in these three areas.

Date: October 1, 1991

Creator: Udagawa, T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Collisionally excited few-electron systems: theoretical introduction and survey. [2-200 keV]

We consider excitation, ionization, and charge transfer in collisions of protons (and antiprotons) with the single-electron targets H, He/sup +/, and Li/sup 2 +/. These collisions are first compared to other types of ion-atom collisions. A brief review of our own theoretical method is given; in particular we describe how we allow for both large charge transfer and ionization probabilities while retaining the computational efficiency that allows us to consider a variety of collision partners and… more

Date: January 1, 1982

Creator: Ford, A.L.; Reading, J.F. & Becker, R.L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Vapor phase spectroscopy of complex lanthanide halide--aluminum halide molecular species

The absorption spectrum of ErCl/sub 3/ (AlCl/sub 3/)/sub x/ vapor complex was measured and analyzed using the Judd-Ofelt theory. Structural correlations in other AlCl/sub 3/ vapor complexes and radiation emission are discussed. Fluorescence of TbCl/sub 3/ (AlCl/sub 3/)/sub x/ vapor complex and in the NdCl/sub 3/ (AlCl/sub 3/)/sub x/ system were studied. (DLC)

Date: January 1, 1977

Creator: Carnall, W T; Hessler, J P; Williams, C W & Hoekstra, H R

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Distortion of He emission lines after fast-ion collisions

After excitation by fast ions (velocity = 2 to 5 au) the emission line profiles of doubly-excited helium atoms are observed to differ significantly from the normal shape of Beutler-Fano resonances. This difference is attributed to the Coulomb interaction between the emitted electron and the ion used to excite the atom. We explain the effect quantitatively with a simple classical model combined with a post-collision-interaction theory. 4 refs., 4 figs.

Date: January 1, 1985

Creator: Arcuni, P. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Progress in collisions of multiply charged ions

The increasing power and availability of supercomputers during the last decade led to significant progress in the theory of multicharged ion interactions. However, important tests of many theoretical predictions were lacking, and have become possible only quite recently as new capabilities have been realized in the laboratory. This paper broadly surveys some of these experimental developments, and their impact on our understanding of collisional interactions of multicharged ions. The scope is l… more

Date: January 1, 1991

Creator: Phaneuf, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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University of Chicago technical progress report covering September 1, 1974--August 31, 1975. [Electronic and vibrational excitations of ordered and disordered solids]

No Description Available.

Date: January 1, 1975

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Processes of energy deposition by heavy particle impact. Technical report No. 2

Experimental studies of the Li/sup +/ + He interaction have been extended to smaller internuclear separations to clarify a discrepancy between experiment and theory in the elastic cross sections and to observe and measure cross sections for inelastic excitation. For R less than or equal to 0.5 a/sub 0/ the elastic scattering differential cross section is observed to droop far below that expected from a single-state interaction based on ab initio ground-state potentials. In this same region of R… more

Date: July 6, 1971

Creator: Lorents, D. C. & Conklin, G. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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IBA in deformed nuclei

The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for /sup 168/Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong ..beta.. ..-->.. ..gamma.. transitions, a feature characteristically absent in the geometrical model, but manifest em… more

Date: January 1, 1982

Creator: Casten, R. F. & Warner, D. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Excitation of high-n toroidicity-induced shear Alfven eigenmodes by energetic particles and fusion alpha particles in tokamaks

The stability of high-n toroidicity-induced shear Alfven eigenmodes (TAE) in the presence of fusion alpha particles or energetic ions in tokamaks is investigated. The TAE modes are discrete in nature and thus can easily tap the free energy associated with energetic particle pressure gradient through wave particle resonant interaction. A quadratic form is derived for the high-n TAE modes using gyro-kinetic equation. The kinetic effects of energetic particles are calculated perturbatively using t… more

Date: July 1, 1992

Creator: Fu, G. Y. & Cheng, C. Z.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Atomic and molecular science with synchrotron radiation

This paper discusses the following topics: electron correlation in atoms; atomic innershell excitation and decay mechanisms; timing experiments; x-ray scattering; properties of ionized species; electronic properties of actinide atoms; total photon-interaction cross sections; and molecular physics. 66 refs. (LSP)

Date: November 7, 1989

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The Collective Vector method in nuclear and atomic physics

We present a brief review of the method of the Collective Vector (CV) and its use in conjunction with the Lanczos algorithm (LA). The combination of these two ideas produces a method for contracting super-large hamiltonians (up to 10{sup 6} {times} 10{sup 6}) by factors of 1000 or more. The contracted hamiltonians, which we call quasi-hamiltonians, typically have dimensions of the order of 10{sup 2} {times} 10{sup 2} and produce corresponding quasi-spectra with associated quasi-eigenfunctions w… more

Date: December 1, 1989

Creator: Bloom, S.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Harmonic launching of ion Bernstein waves via mode transformation

Ion Bernstein wave excitation and propagation via finite ion-Larmor-radium mode-transformation are investigated theoretically and experimentally. It is shown that in the ion cyclotron range of frequencies omega less than or equal to 4..cap omega../sub i/, with modest ion temperatures (T/sub i/ less than or equal to 10 eV), the finite-Larmor-radius effect removes the wave singularity at lower-hybrid resonance layer, enabling an externally initiated electron plasma wave to transform continuously … more

Date: June 1, 1982

Creator: Ono, M.; Wong, K. L. & Wurden, G. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Versatile 0. 5 TW electron beam facility for power conditioning studies of large rare-gas/halide lasers

Rare-gas/halide lasers which are being developed for Inertial Confinement Fusion will require large area, low impedance electron beam drivers. A wide range of electron beam parameters are being considered for future systems in an effort to optimize the overall system design. A number of power conditioning issues must be investigated in order to obtain a better understanding of the various trade-offs involved in making such optimizations. The RAYITO electron beam accelerator is being designed an… more

Date: January 1, 1980

Creator: Ramirez, J. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Mayer-Fermi Theory and the Long Sequences in the Periodic Table

Changes in the radial wave functions for d electrons which occur preceding the onset of the transition series of elements and for f electrons preceding the onset of the lanthanide and actinide series are examined. The sensitivity of the radial wave functions to variations in the effective potential is discussed, and the large variation in the radial wave functions between the LS terms of certain types of excited configurations in these regions of the periodic system is analyzed. Several example… more

Date: January 1, 1986

Creator: Griffin, D. C.; Cowan, R. D. & Pindzola, M. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Fast-neutron total and scattering cross sections of sup 58 Ni and nuclear models

The neutron total cross sections of {sup 58}Ni were measured from {approx} 1 to > 10 MeV using white-source techniques. Differential neutron elastic-scattering cross sections were measured from {approx} 4.5 to 10 MeV at {approx} 0.5 MeV intervals with {ge} 75 differential values per distribution. Differential neutron inelastic-scattering cross sections were measured, corresponding to fourteen levels with excitations up to 4.8 MeV. The measured results, combined with relevant values available in… more

Date: July 1, 1991

Creator: Smith, A. B.; Guenther, P. T.; Whalen, J. F. (Argonne National Lab., IL (United States)) & Chiba, S. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment)

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Superdeformed nuclei

This paper reviews the most recent advances in the understanding of the physics of superdeformed nuclei from the point of view of the experimentalists. It covers among other subjects the following topics: (1) the discovery of a new region of superdeformed nuclei near A=190, (2) the surprising result of the occurrence of bands with identical transition energies in neighboring superdeformed nuclei near A=150 and A=190, (3) the importance of octupole degrees of freedom at large deformation and (4)… more

Date: January 1, 1991

Creator: Janssens, R.V.F. & Khoo, Teng Lek.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Rotational population patterns and searches for the nuclear SQUID (Superconducting Quantum Interference Device)

This paper presents new theoretical results for rotational population patterns in the nuclear SQUID effect. (The term nuclear SQUID is in analogy to the solid-state Superconducting Quantum Interference Devices.) The SQUID effect is an interesting new twist to an old quest to understand Coriolis anti-pairing (CAP) effects in nuclear rotational bands. Two-neutron transfer reaction cross sections among high-spin states have long been touted as more specific CAP probes than other nuclear properties… more

Date: November 1, 1989

Creator: Canto, L.F.; Donangelo, R.J.; Farhan, A.R.; Guidry, M.W.; Rasmussen, J.O.; Ring, P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Correlation theory applied to the static and dynamic properties of EuO and EuS

The paramagnetic scattering was recently measured for EuO. It was found that spin-wave-like excitations develop for wave vectors approaching the zone boundary. The spectrum was found to be well described by damped harmonic oscillators (also called the two-pole-approximation). This approximation was used previously in the correlation theory primarily to calculate static properties. Selfconsistent dynamic and static calculations have been performed for EuO, which is an ideal Heisenberg magnet wit… more

Date: October 1, 1981

Creator: Lindgard, P.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Stimulated vuv radiation from HD excited by a picosecond ArF laser

Stimulated emission on E,F ..-->.. B, B ..-->.. X, and C ..-->.. X transitions of HD is observed following two-photon excitation in the E,F state with a picosecond ArF* laser. The efficiency of the strongest B ..-->.. X line is approx.1%. Electron collisions are found to play an important role for C ..-->.. X emissions. 12 refs., 1 fig.

Date: January 1, 1984

Creator: Luk, T.S.; Egger, H.; Mueller, W.; Pummer, H. & Rhodes, C.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Radiological and Environmental Research Division annual report, October 1978-September 1979. Part I. Fundamental molecular physics and chemistry

Research on the chemical physics of atoms and molecules, especially their interaction with external agents such as photons and electrons is reported. Abstracts of seven individual items from the report were prepared separately for the data base. (GHT)

Date: January 1, 1979

Item Type: Report

Partner: UNT Libraries Government Documents Department