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in subjects: "Ground States"

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Photodissociation of the Propargyl (C3D3) Radicals at 248 nm and 193 nm

The photodissociation of perdeuterated propargyl (D{sub 2}CCCD) and propynyl (D{sub 3}CCC) radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 nm and 450 nm (below and above the electron affinity of propynyl). The radicals were then photodissociated by 248 nm or 193 nm light. The recoiling photofragments were detected in coincidence with a time- and position-sensitive detector. Three ch… more

Date: January 21, 2009

Creator: Neumark, Daniel M.; Crider, Paul E.; Castiglioni, Luca & Kautzman, Kathryn E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Single Quark Transition Model Analysis of Electromagnetic Nucleon Resonance Excitations

We apply the single quark transition model to resonance transition amplitudes extracted from photo- and electroproduction data. We use experimental data on the S{sub 11}(1535), and D{sub 13}(1520) nucleon resonances to extract the amplitudes for the electromagnetic transition from the nucleon ground state [56,0+] to the [70,1-] supermultiplet, and make predictions for the transition amplitudes of all other states associated with the [70,1-]. We compare the predictions with data and find surpris… more

Date: August 1, 2002

Creator: Burkert, V.D.; Vita, R. De; Battaglieri, M.; Ripani, M. & Mokeev, V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ISOTOPE METHODS IN HOMOGENEOUS CATALYSIS.

The use of isotope labels has had a fundamentally important role in the determination of mechanisms of homogeneously catalyzed reactions. Mechanistic data is valuable since it can assist in the design and rational improvement of homogeneous catalysts. There are several ways to use isotopes in mechanistic chemistry. Isotopes can be introduced into controlled experiments and followed where they go or don't go; in this way, Libby, Calvin, Taube and others used isotopes to elucidate mechanistic pat… more

Date: December 2000

Creator: Bullock, R. M. & Bender, B. R.

Item Type: Book

Partner: UNT Libraries Government Documents Department

open access

THEORY OF PROTON EMITTERS

Modern theoretical methods used to interpret recent experimental data on ground-state proton emission near the proton drip line are reviewed. Most of them are stationary and are aimed to compute proton decay widths {Gamma}{sub p} only. Comparison is made between these approaches before being compared to experimental data. Our time-dependent approach based on the numerical solution of the time-dependent Schroedinger equation (TDSE) for initial quasi-stationary single-proton states is then introd… more

Date: August 1, 2000

Creator: TALOU, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Relativity damps OPEP in nuclear matter

Using a relativistic Dirac-Brueckner analysis the OPEP contribution to the ground state energy of nuclear matter is studied. In the study the pion is derivative-coupled. The author finds that the role of the tensor force in the saturation mechanism is substantially reduced compared to its dominant role in a usual nonrelativistic treatment. He shows that the damping of derivative-coupled OPEP is actually due to the decrease of M{sup *}/M with increasing density. He points out that if derivative-… more

Date: June 1, 1998

Creator: Banerjee, M.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Thermodynamic ground states of platinum metal nitrides

We have systematically studied the thermodynamic stabilities of various phases of the nitrides of the platinum metal elements using density functional theory. We show that for the nitrides of Rh, Pd, Ir and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower formation enthalpies at ambient conditions than any previously proposed structures. The region of stability can extend up to 17 GPa for PtN{sub 2}. Furthermore, we show that according to… more

Date: October 9, 2007

Creator: Aberg, D; Sadigh, B; Crowhurst, J & Goncharov, A

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Observation of the Bottomonium Ground State in the Decay Y(3S) to ynb

The authors report the results of a search for the bottomonium ground state {eta}{sub b}(1S) in the photon energy spectrum with a sample of (109 {+-} 1) million of {Upsilon}(3S) recorded at the {Upsilon}(3S) recorded at the {Upsilon}(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. They observe a peak in the photon energy spectrum at E{sub {gamma}} = 921.2{sub -2.8}{sup +2.1}(stat) {+-} 2.4(syst) MeV with a significance of 10 standard deviations. They interpret the observed p… more

Date: July 11, 2008

Creator: Aubert, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structures of High Density Molecular Fluids

The goal of this proposal is to develop an in-situ probe for high density molecular fluids. We will, therefore, use Coherent Anti-Stokes Raman Spectroscopy (CARS) applied to laser heated samples in a diamond-anvil cell (DAC) to investigate molecular fluids at simultaneous conditions of high temperatures (T > 2000K) and high pressures (P > 10 GPa.) Temperatures sufficient to populate vibrational levels above the ground state will allow the vibrational potential to be mapped by CARS. A syst… more

Date: February 1, 2002

Creator: Baer, B.; Cynn, H.; Iota, V. & Yoo, C. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Electronic Structure for the Ground State of t1h From Relativistic Multiconfiguration Scf Calculations

The dissociation curve for the ground state of TlH was computed using a relativistic {omega}-{omega} coupling formalism. The relativistic effects represented by the Dirac equation were introduced using effective potentials generated from atomic Dirac-Fock wave functions using a generalization of the improved effective potential formulation of Christiansen, Lee, and Pitzer. The multiconfiguration SCF treatment used is a generalization of the two-component molecular spinor formalism of Lee, Ermle… more

Date: July 1, 1980

Creator: Christiansen, P. A. & Pitzer, K. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Myriad phases of the Checkerboard Hubbard Model

The zero-temperature phase diagram of the checkerboard Hubbard model is obtained in the solvable limit in which it consists of weakly coupled square plaquettes. As a function of the on-site Coulomb repulsion U and the density of holes per site, x, we demonstrate the existence of at least 16 distinct phases. For instance, at zero doping, the ground state is a novel d-wave Mott insulator (d-Mott), which is not adiabatically continuable to a band insulator; by doping the d-Mott state with holes, d… more

Date: April 6, 2010

Creator: Yao, Hong

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Spin Equilibria in Monomeric Manganocenes: Solid State Magnetic and EXAFS Studies

Magnetic susceptibility measurements and X-ray data confirm that tert-butyl-substituted manganocenes [(Me{sub 3}C){sub n}C{sub 5}H{sub 5?n}]{sub 2}Mn (n = 1, 2) follow the trend previously observed with the methylated manganocenes; that is, electron-donating groups attached to the Cp ring stabilize the low-spin (LS) electronic ground state relative to Cp{sub 2}Mn and exhibit higher spin-crossover (SCO) temperatures. However, introducing three CMe{sub 3} groups on each ring gives a temperature-i… more

Date: February 9, 2009

Creator: Walter, M. D.; Sofield, C. D.; Booth, C. H. & Andersen, R. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

THE DYNAMICS OF HYDROGEN ATOM ABSTRACTION FROM POLYATOMIC MOLECULES.

The hydrogen atom abstraction reaction is an important fundamental process that is extensively involved in atmospheric and combustion chemistry. The practical significance of this type of reaction with polyatomic hydrocarbons is manifest, which has led to many kinetics studies. The detailed understanding of these reactions requires corresponding dynamics studies. However, in comparison to the A + HX {radical} AH + X reactions, the study of the dynamics of A + HR {yields} AH + R reactions is muc… more

Date: November 21, 2002

Creator: Liu, X. & Suits, A. G.

Item Type: Book

Partner: UNT Libraries Government Documents Department

open access

Jahn-Teller splitting and Zeeman effect of acceptors in diamond.

Employing the high resolution of a 5+4 tandem Fabry-Perot interferometer, we discovered that {Delta}{prime}, the Raman active electronic transition between the spin-orbit split 1s(p{sub 3/2}): {Lambda}{sub 8} and 1s(P{sub 1/2}) {Lambda}{sub 7} acceptor ground states, is a doublet for a boron impurity in diamond with a clearly resolved spacing of 0.81 {+-} 0.15 cm{sup {minus}1}. The direct observation of a Stokes/anti-Stokes pair with 0.80 {+-} 0.04 cm{sup {minus}1} shift provides a striking con… more

Date: September 11, 1999

Creator: Anthony, T. R.; Grimsditch, M.; Kim, H.; Ramdas, A. K. & Rodriguez, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Neutron Scattering Studies of the Chains and Ladders in Sr{sub 14}Cu{sub 24}O{sub 41} and Related Compounds

A review is given of the neutron scattering studies on the S=1/2 quasi-one-dimensional magnet Sr14Cu24O41 and related compounds which have both simple chains and two-leg ladders of copper ions. Both of the building blocks show interesting singlet ground states and magnetic excitations. In this system it is possible to change the number of hole carriers by substitution for Sr. A dramatic change has been observed in the ground state and the magnetic excitations with decreasing the number of holes. more

Date: Autumn 1997

Creator: Matsuda, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Selective excitation of the yellow and blue luminescence in n- and p-doped Gallium Nitride

GaN is an interesting material: technologically very useful, but still having many unexplained features. Two such features are the broad defect-related luminescence bands: the YL of n-type GaN and the BL of Mg-doped p-type GaN. We have employed selective excitation to investigate these bands. In the case of the YL, most of the previous evidence has supported a recombination model between distant donors and acceptors, most likely a transition involving a shallow donor to a deep acceptor. Our sel… more

Date: December 31, 2000

Creator: Colton, John S.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model

We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a dramatic reduction of the basis dimension. We analyze the validity and efficiency of this truncation scheme using differen… more

Date: May 22, 2007

Creator: Roth, R & Navratil, P

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Cerocene Revisited: The Electronic Structure of and Interconversion Between Ce2(C8H8)3 and Ce(C8H8)2

New synthetic procedures for the preparation of Ce(cot)2, cerocene, from [Li(thf)4][Ce(cot)2], and Ce2(cot)3 in high yield and purity are reported. Heating solid Ce(cot)2 yields Ce2(cot)3 and COT while heating Ce2(cot)3 with an excess of COT in C6D6 to 65oC over four months yields Ce(cot)2. The solid state magnetic susceptibility of these three organocerium compounds shows that Ce(cot)2 behaves as a TIP (temperature independent paramagnet) over the temperature range of 5-300 K, while that of Ce… more

Date: February 2, 2009

Creator: Walter, Marc D.; Booth, Corwin H.; Lukens, Wayne W. & Andersen, Richard A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Prospects for studies of ground-state proton decays with the Holifield Radioactive Ion Beam Facility

By using radioactive ions from the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory it should be possible to identify many new ground-state proton emitters in the mass region from Sn to Pb. During this production and search process the limits of stability on the proton-rich side of the nuclidic chart will be delineated for a significant fraction of medium-weight elements and our understanding of the proton-emission process will be expanded and improved.

Date: February 1, 1994

Creator: Toth, K. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quantifying exchange coupling in f-ion pairs using the diamagnetic substitution method

One of the challenges in the chemistry of actinide and lanthanide (f-ion) is quantifying exchange coupling between f-ions. While qualitative information about exchange coupling may be readily obtained using the diamagnetic substitution approach, obtaining quantitative information is much more difficult. This article describes how exchange coupling may be quantified using the susceptibility of a magnetically isolated analog, as in the diamagnetic substitution approach, along with the anisotropy … more

Date: April 1, 2010

Creator: Lukens, Wayne W. & Walter, Marc D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Bottomonium Results By BaBar

Summary: Observation of {eta}{sub b}; Energy scan above {Upsilon}(4S); Search for {Upsilon} {r_arrow} {gamma}A{sup 0}, A{sup 0} {r_arrow} invisible; Hadronic transitions {Upsilon}(4S) {r_arrow} {Upsilon}(nS).

Date: April 3, 2012

Creator: Tosi, Silvano & /Genoa U. /INFN, Genoa

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Predictive model of nucleon-nucleus scattering cross sections

Nucleon total reaction and neutron total cross sections as well as differential (including spin) observables from 25 to 300 MeV for stable nuclei from 6Li to 238U have been predicted that are in good agreement with measured data. Those predictions have been made using non-local, energy dependent, and complex optical potentials in coordinate space formed by full folding of effective nucleon-nucleon interactions with realistic nuclear ground state densities. By inverse kinematics the same model p… more

Date: January 1, 2001

Creator: Amos, K. (Ken); Deb, P. (Pradip); Karataglidis, S. (Steven) & Madland, D. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Beta-decay half-lives and beta-delayed neutron emisison probabilities of nuclei in the region A. 110, relevant for the r-process

Measurements of the {beta}-decay properties of A {approx}< 110 r-process nuclei have been completed at the National Superconducting Cyclotron Laboratory, at Michigan State University. {beta}-decay half-lives for {sup 105}Y, {sup 106,107}Zr and {sup 108,111}Mo, along with ,B-delayed neutron emission probabilities of 104Y, 109,11OMo and upper limits for 105Y, 103-107Zr and 108,111 Mo have been measured for the first time. Studies on the basis of the quasi-random phase approximation are used to… more

Date: January 1, 2009

Creator: Moller, Peter; Pereira, J.; Hennrich, S.; Aprahamian, A.; Arndt, O.; Becerril, A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Experimental evidence of a dynamic Jahn-Teller effect in C-60(+)

Detailed analysis of the HOMO bandshape in the photoelectron spectrum of gaseous C60 reveals a dynamic Jahn-Teller effect in the ground state of C60+. The direct observation of three tunneling states asserts a D3d geometry for the isolated cation, originating from a strong vibronic coupling. These results show that the ionic motion of the ions plays an important role in the electron-phonon interaction.

Date: May 20, 2002

Creator: Canton, S.E.; Yencha, A.J.; Kukk, E.; Bozek, J.D.; Lopes, M.C.A.; Snell, G. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Complex potential surface for the {sup 2}B{sub 1} metastable state of the water anion

The potential energy surface corresponding the complex resonance energy of the 2B1 Feshbach resonance state of the water anion is constructed in its full dimensionality. Complex Kohn variational scattering calculations are used to compute the resonance width, while large-scale Configuration Interaction calculations are used to compute the resonance energy. Near the equilibrium geometry, an accompanying ground state potential surface is constructed from Configuration Interaction calculations tha… more

Date: April 23, 2004

Creator: Haxton, Daniel J.; Zhang, Zhiyong; McCurdy, C. William & Rescigno, Thomas N.

Item Type: Article

Partner: UNT Libraries Government Documents Department