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in subjects: "Ground States"

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Microscopic and semi-classical treatments of octupole deformation in the light actinides

Microscopic and semi-classical descriptions of octupole deformation are compared. New semi-classical results, obtained with the use of a Woods-Saxon potential are presented. Comparisons with experiment are made. 21 references.

Date: January 1, 1984

Creator: Chasman, R.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Sources of polarized ions and atoms

In this presentation we discuss methods of producing large quantities of polarized atoms and ions (Stern-Gerlach separation, optical pumping, and spin-exchange) as well as experimental methods of measuring the degree of polarization of atomic systems. The usefulness of polarized atoms in probing the microscopic magnetic surface properties of materials will also be discussed. 39 refs., 5 figs., 2 tabs.

Date: January 1, 1988

Creator: Cornelius, W.D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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VUV (vacuum ultraviolet) laser diagnostics of H sup - ion sources

Vacuum ultraviolet laser absorption spectroscopy has been employed to measure the populations and temperatures of ground electronic state H-atoms and vibrationally-excited H{sub 2} molecules in a volume H{sup -} ion source. Measurements of both species have been made under a variety of discharge conditions. Vibrational levels to v{double prime}=8 have been measured, with the vibrational population distribution well described by a temperature of 4150K. 10 refs., 9 figs.

Date: November 1, 1989

Creator: Young, A. T.; Stutzin, G. C.; Leung, K. N. & Kunkel, W. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Microscopic calculations of nuclear structure and nuclear correlations

A major goal in nuclear physics is to understand how nuclear structure comes about from the underlying interactions between nucleons. This requires modelling nuclei as collections of strongly interacting particles. Using realistic nucleon-nucleon potentials, supplemented with consistent three-nucleon potentials and two-body electroweak current operators, variational Monte Carlo methods are used to calculate nuclear ground-state properties, such as the binding energy, electromagnetic form factor… more

Date: January 1, 1992

Creator: Wiringa, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ground state of the electron gas by a stochastic method

An exact stochastic simulation of the Schroedinger equation for charged Bosons and Fermions was used to calculate the correlation energies, to locate the transitions to their respective crystal phases at zero temperature within 10%, and to establish the stability at intermediate densities of a ferromagnetic fluid of electrons.

Date: May 1, 1980

Creator: Ceperley, D. M. & Alder, B. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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New method to determine the chemical composition and structure of non-elemental acceptor and donor centers in ultra-pure germanium

A new approach towards the understanding of hitherto unknown, non-elemental acceptors and donors which can limit the purity of ultra-pure germanium has been explored for a specific pair of shallow centers, designated A/sub 2/ and D. Using photoelectric spectroscopy, we have demonstrated that an isotope shift in the ground-state binding energy occurs when the germanium crystals are grown in pure deuterium instead of in the usual pure hydrogen atmosphere. This isotope shift is the most direct pro… more

Date: October 1, 1977

Creator: Haller, E.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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/sup 194/ /sup 196/ /sup 198/Pt(t,. cap alpha. )/sup 193/ /sup 195/ /sup 197/Ir reactions with polarized tritons. [17 MeV]

The /sup 194/ /sup 196/ /sup 198/Pt(t vector, ..cap alpha..)/sup 193/ /sup 195/ /sup 197/Ir reactions were measured. Angular distributions of cross sections and analyzing powers for levels up to approx. 2.5 MeV in each residual nuclide were obtained, and comparisons with DWBA predictions allowed spins, parities, and pickup spectroscopic strengths to be determined. The results are being analyzed with the aim of testing the existence of supersymmmetric structures in nature. 2 figures.

Date: January 1, 1980

Creator: Cizewski, J. A.; Flynn, E. R.; Sunier, J. W.; Brown, R. E. & Burke, D. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A = 4 0/sup +/ - 1/sup +/ binding-energy difference

The A = 4 ..lambda..-hypernuclei provide a rich source of information about the s-wave properties of the fundamental hyperon-nucleon (YN) force as well as offer a unique opportunity to investigate the complications that arise in calculations of the properties of bound systems in which one baryon (here the ..lambda..) with a given isospin couples strongly to another (the ..sigma..) with a different isospin. The ..lambda../sup 4/H - ..lambda../sup 4/He isodoublet ground-state energies are not con… more

Date: January 1, 1982

Creator: Gibson, B. F. & Lehman, D. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Studies in Hot Atom and Radiation Chemistry Progress Report: September 1977

The reactive scattering of the reaction of the first excited state of C/sup +/ (/sup 4/P) with molecular hydrogen was studied over an energy range of 0.5 to 9.0 eV. The measurements indicate that the reaction proceeded by a direct mechanism and the final product was in the a/sup 3/pi state. The reaction of ground-state C/sup +/(/sup 2/P) with D/sub 2/ and H/sub 2/ was examined over the energy range of 2.5 eV to 28 eV. Over this energy range unambiguous identification of CD/sup +/ in the X/sup 1… more

Date: January 1, 1977

Creator: Koski, W. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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A kinetics study of the O( sup 3 P) + CH sub 3 Cl reaction over the 556-1485 K range by the HTP and LP-ST techniques

The high-temperature photochemistry (HTP) and laser photolysis-shock tube (LP-ST) techniques have been combined to study the kinetics of the reaction between ground-state oxygen atoms with CH{sub 3}Cl over the temperature range, 556--1485 K. In the HTP reactor, used for the 556--1291 K range, O atoms were generated by flash photolysis of O{sub 2}, CO{sub 2} or SO{sub 2}, and the atom concentrations were monitored by resonance fluorescence, while with the LP-ST technique, used for the 916--1485 … more

Date: December 1, 1991

Creator: Ko, Taeho; Fontijn, A. (Rensselaer Polytechnic Inst., Troy, NY (United States). High-Temperature Reaction Kinetics Lab.); Lim, K.P. & Michael, J.V. (Argonne National Lab., IL (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Shell-Model Calculations of Nuclear-Charge Radii

Shell-model calculations of charge radius differences in the Pb isotopes are discussed. Core quadrupole oscillations are found to be significant factors in the calculations. Existing data on the /sup 210/Pb isotope shift and the B(E2) strengths in /sup 210/Pb are shown to be inconsistent. Ground-state correlation effects in light nuclei (i.e., 0 and Ca isotopes) introduce odd-even staggering effects and other qualitative features in agreement with existing data.

Date: January 1, 1982

Creator: McGrory, J. B. & Brown, B. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Calculations of the ground state of sup 16 O

One of the central problems in nuclear physics is the description of nuclei as systems of nucleons interacting via realistic potentials. There are two main aspects of this problem: specification of the Hamiltonian, and calculation of the ground states of nuclei with the given interaction. Realistic interactions must contain both two- and three-nucleon potentials and these potentials have a complicated non-central operator structure consisting, for example, of spin, isospin and tensor dependence… more

Date: January 1, 1989

Creator: Pieper, S. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Decay of mass-separated /sup 118/Ag to levels in /sup 118/Cd

A study of the gamma-ray de-excitation following the beta decay of /sup 118/Ag using the TRISTAN on-line isotope separator is reported. Gamma-ray singles, gamma-gamma coincidence, and gamma-ray multiscale measurements were made using Ge(Li) detectors. A total of 52 gamma rays were observed in the decay of /sup 118/Ag. Thirty-eight of these were placed in a level scheme for /sup 118/Cd consisting of 20 excited states up to 3382 keV. Gamma-ray multiscale measurements indicated that /sup 118/Ag ha… more

Date: April 1, 1978

Creator: Margetan, D. R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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3-body final states in peripheral heavy-ion collisions: nuclear clustering structure and projectile excitation revisited

Even though peripheral heavy-ion collisions are less violent than their central counterparts, the large energy exchange between the reactants often leaves the primary products in excited particle-unstable states whose subsequent decay leads to 3 or more nuclei emerging in the final exit channel. These post-reaction, predominantly sequential de-excitation processes can sometimes provide interesting structural information about the parent nuclei. In fact, provided these processes are well underst… more

Date: February 1, 1986

Creator: Chan, Y.; Chavez, E.; Gazes, S.B.; Kamermans, R.; Schmidt, H.R.; Siwek-Wilczynska, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Laser measurements and nuclear structure

The nuclear states amenable to laser studies are reviewed with respect to their structure. Systematic predictions are made, e.g., for magnetic moments of parity-mixed intrinsic orbitals in the Ac isotopes and for the shape of the known high-spin isomers in the Pb region.

Date: January 1, 1982

Creator: Leander, G.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The sup 11 Li neutron halo radius from pion double charge exchange

We have analyzed the pion double charge exchange data for the direct population of the ground state of {sup 11}Li by the {sup 11}B({pi}{sup minus},{pi}{sup +}){sup 11}Li reaction and find that the measured cross section determines the rms radius of the last two neutrons in {sup 11}Li to be 5.1{sub {minus}0.8}{sup +0.6} fm. 8 refs., 2 figs.

Date: January 1, 1991

Creator: Gibbs, W.R. & Hayes, A.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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de Haas van Alphen effect in high temperature superconductors

The de Haas van Alphen effect has been investigated using 100 tesla fields and temperatures below 4.2 Kelvin. It is concluded from these measurements that YBCO exhibits a Fermi surface with at least three separate extremal frequencies for the c-axis parallel to the applied field. Orbital masses, renormalization g's and scattering rates are estimated from an amplitude analysis. 16 refs., 2 figs.

Date: January 1, 1991

Creator: Mueller, F.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Variational methods for field theories

Four field theory models are studied: Periodic Quantum Electrodynamics (PQED) in (2 + 1) dimensions, free scalar field theory in (1 + 1) dimensions, the Quantum XY model in (1 + 1) dimensions, and the (1 + 1) dimensional Ising model in a transverse magnetic field. The last three parts deal exclusively with variational methods; the PQED part involves mainly the path-integral approach. The PQED calculation results in a better understanding of the connection between electric confinement through mo… more

Date: September 1, 1986

Creator: Ben-Menahem, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Effect of the nuclear equation of state on high-energy heavy-ion collisions

The effect of the nuclear equation of state on high-energy heavy-ion collisions is studied in two separate ways on the basis of conventional nuclear fluid dynamics. The equation of state has the property that the speed of sound approaches the speed of light in the limit of infinite compression. In the first way, nonrelativistic equations of motion are solved for various values of the nuclear compressibility coefficient for the expansion of spherically symmetric nuclear matter. The matter is ini… more

Date: January 1, 1980

Creator: Nix, J. R.; Sierk, A. J. & Strottman, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Present status of the VMI and related models

This article traces the evolution of the Variable Moment of Inertia model in its relation to the shell model, the Bohr-Mottelson model and the Interacting Boson Model. The discovery of a new type of spectrum, that of pseudomagic nuclei (isobars of doubly magic nuclei) is reported, and an explanation for their dynamics is suggested. The type of rotational motion underlying the ground state band of an e-e nucleus is shown to depend on whether the minimum number of valence nucleon pairs of one kin… more

Date: May 1, 1980

Creator: Scharff-Goldhaber, G

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A new symmetry in collective motion

The purity of intrinsic states of nuclei with respect to a proton-neutron boson symmetry (F-spin) is shown to be largely determined by the difference between proton and neutron deformations and not by whether the Hamiltonian is an F-spin scalar. F-spin mixing in the ground state band of {sup 165}Ho is estimated using recent pion single-charge-exchange data. A B(M1) sum rule is derived using F-spin symmetry. 27 refs., 1 fig.

Date: January 1, 1991

Creator: Ginocchio, J.N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electronegative gases

Recent knowledge on electronegative gases essential for the effective control of the number densities of free electrons in electrically stressed gases is highlighted. This knowledge aided the discovery of new gas dielectrics and the tailoring of gas dielectric mixtures. The role of electron attachment in the choice of unitary gas dielectrics or electronegative components in dielectric gas mixtures, and the role of electron scattering at low energies in the choice of buffer gases for such mixtur… more

Date: January 1, 1981

Creator: Christophorou, L.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Crystal-Field Spectroscopy of UCL4 by Neutron Inelastic Scattering

The crystal-field level scheme of uranium tetrachloride has been the subject of a number of investigations by both optical and magnetic measurements. Agreement does not exist. To attempt to resolve this problem we have performed experiments with the pulsed neutron source at ANL which allows electronic spectroscopy to be extended to approx.2000 cm/sup -1/. Initially using incident energies of 400 cm/sup -1/ we examined the GAMMA/sub 4/ (ground state) to GAMMA/sub 5/ (excited state) level with th… more

Date: January 1, 1985

Creator: Delamoye, P.; Krupa, J. C.; Kern, S.; Loong, C. K. & Lander, G. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Theoretical studies of highly ionized species. Progress report, March 1, 1977--February 28, 1978

The relativistic random phase approximation has been used to study the helium, beryllium, magnesium and zinc isoelectronic sequences. Model potential methods have been employed to study multi-photon ionization of sodium from the ground and excited states. Forbidden decays in the Be and Mg isoelectronic sequences have been investigated. The 1s2p/sup 2/ /sup 2/P and 1s2p/sup 2/ /sup 2/D states of lithium-like ions have been studied. Calculations of radiative charge transfer have been carried out.

Date: November 1, 1977

Creator: Dalgarno, A. & Victor, G.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department