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Test of {Delta}I = 2 staggering in the superdeformed bands of {sup 194}Hg

Description: Superdeformed (SD) states in {sup 194}Hg were populated in {sup 150}Nd({sup 48}Ca,4n) using a 201 MeV {sup 48}Ca beam from the 88- inch cyclotron. A high statistics experiment was done to test for the previously reported evidence for a {Delta}I = 2 staggering in the three SD bands in {sup 194}Hg. The transition energies were determined with a precision of at least 60 eV for most transitions. From this improvement, we cannot confirm evidence for an extended regular {Delta}I = 2 staggering in any… more
Date: November 1996
Creator: Kruecken, R.; Deleplanque, M. A. & Hackman, G.
Partner: UNT Libraries Government Documents Department
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Precision measurements of atomic lifetimes in alkali like systems. Progress report, September 15, 1995--January 15, 1998

Description: Precision measurements of atomic lifetimes are important to the analysis of data from many areas of physics and provide fundamental atomic structure information. Scientists in the fields of astrophysics, geophysics, and plasma fusion all depend on oscillator strengths to determine the relative abundances of elements. Assessing the operation of discharge lamps and atomic resonance line filters also depends on knowing accurately atomic oscillator strengths. Often relative values of oscillator str… more
Date: January 1, 1998
Creator: Tanner, C. E.
Partner: UNT Libraries Government Documents Department
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Hyperfine quenching of the 2$sup 3$P$sub 0$ state in heliumlike ions

Description: An estimate is presented of the lifetime of the 2$sup 3$P$sub 0$ state for odd-Z heliumlike ions in the range Z = 9 to 29. An approximation scheme is employed which utilizes the fact that both Z$sup -1$ and (Z$alpha$)$sup 2$ are small parameters for the range of Z under consideration. 1 fig, 2 tables, 14 refs. (GHT)
Date: November 19, 1975
Creator: Mohr, P. J.
Partner: UNT Libraries Government Documents Department
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Identification of Electronic Transitions in Polyacetylene by Acoustic Phonon Spectroscopy

Description: We have found that a strain-induced oscillation in the decay of the picosecond photoinduced absorption of polyacetylene (CH){sub x} can be used to identify the allowed and forbidden electronic transitions in that polymer.
Date: April 1, 1994
Creator: Kanner, G. S.; Lanzani, G. & Vardeny, Z. V.
Partner: UNT Libraries Government Documents Department
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Collisional population transfer in yterbium ions

Description: Long-lived metastable states of Yb+ ions are used for atomic frequency standards, precision measurements, and quantum information research. The effect of population trapping and transfer in these states must be well understood. We report here the transfer of Yb+ ions into the long-lived {sup 2}F{sub 7/2} state by means of collisions between He buffer gas and Yb+ ions held in a linear Paul trap. Transfer rates were measured as functions of buffer-gas pressure and repump-laser power, and the coll… more
Date: January 1, 2009
Creator: Schauer, Martin Michael; Torgerson, Justin R; Danielson, Jeremy R; Zhao, Xinxin; Nguyen, Ahn - Tuan & Wang, Li - Bang
Partner: UNT Libraries Government Documents Department
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Magneto-Excitons in (411)A and (100)-Oriented GaAs/AlGaAs Multiple Quantum Well Structures

Description: We report magneto-exciton spectroscopy studies of (411)A and (100)-oriented GaAs/Al{sub 0.3}Ga{sub 0.7}As multiquantum well structures. The samples consisted of seven GaAs quantum wells with widths varying between 0.6 and 12nm, were grown on (411)A and (100)-oriented GaAs substrates. The exciton diamagnetic energy shifts and linewidths were measured between 0 and 14T at 1.4K The dependence of the exciton diamagnetic shifts with magnetic field were calculated using a variational approach and goo… more
Date: January 20, 1999
Creator: Bajaj, K. K.; Hiyamizu, S.; Jones, E. D.; Krivorotov, I.; Shimomura, S. & Shinohara, K.
Partner: UNT Libraries Government Documents Department
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Piezoelectric Effects on the Optical Properties of GaN/Al(x)Ga(1-x)N Multiple Quantum Wells

Description: Piezoelectric effects on the optical properties of GaN/AlGaN multiple quantum wells (MQWS) have been investigated by picosecond time-resolved photoluminescence (PL) measurements. For MQWS with well thickness 30 and 40 the excitonic transition peak positions at 10 K in continuous wave (CW) spectra are red-shifted with respect to the GaN epilayer by 17 meV and 57 meV, respectively. The time-resolved PL spectra of the 30 and 40 well MQWS reveal that the excitonic transition is in fact blue-shifted… more
Date: November 10, 1998
Creator: Botchkarev, A.; Chow, W. W.; Jiang, H. X.; Kim, H. S.; Lin, J. Y. & Morkoc, H.
Partner: UNT Libraries Government Documents Department
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Insights on the local density approximation plasma polarization shift as provided by the optimum potential method

Description: The plasma polarization shift computed with a Local Density Functional model of an ion-sphere model is compared with results calculated using an optimum central field effective exchange potential. Indications are that the bulk of the shift is an artifact of the approximate exchange functional describing the interaction between bound and continuum orbitals in the LDA.
Date: January 18, 1995
Creator: Wilson, B. & Liberman, D.A.
Partner: UNT Libraries Government Documents Department
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Single Quark Transition Model Analysis of Electromagnetic Nucleon Resonance Excitations

Description: 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.
Partner: UNT Libraries Government Documents Department
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High gain x-ray lasers pumped by transient collisional excitation

Description: We present recent results of x-ray laser amplification of spontaneous emission in Ne-like and Ni-like transient collisional excitation schemes. The plasma formation, ionization and collisional excitation can be optimized using two laser pulses of 1 ns and 1 ps duration at table-top energies of 5 J in each beam. High gain of 35 cm{sup -1} has been measured on the 147 {Angstrom} 4d{r_arrow}4p J=0{r_arrow}1 transition of Ni-like Pd and is a direct consequence of the nonstationary population invers… more
Date: June 16, 1998
Creator: Dunn, J., LLNL
Partner: UNT Libraries Government Documents Department
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A theoretical analysis of the reaction between ethyl and molecular oxygen

Description: Using a combination of electronic-structure theory, variational transition-state theory, and solutions to the time-dependent master equation, the authors have studied the kinetics of the title reaction theoretically over wide ranges of temperature and pressure. The agreement between theory and experiment is quite good. By comparing the theoretical and experimental results describing the kinetic behavior, they have been able to deduce a value for the C{sub 2}H{sub 5}-O{sub 2} bond energy of {app… more
Date: December 13, 2000
Creator: Miller, James A.; Klippenstein, Stephen J. & Robertson, Stuart H.
Partner: UNT Libraries Government Documents Department
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Test of {Delta}I = 2 staggering in the superdeformed bands of {sup 194}Hg

Description: The presence of {Delta}I = 2 staggering in the three known superdeformed bands of {sup 194}Hg has been reexamined in a new experiment with Gammasphere. A relative accuracy of better than 30 eV was achieved for most transition energies. No statistically significant oscillations in the transition energies were found for band 1 while staggering patterns were observed in bands 2 and 3. The statistical significance of the observed effects was analyzed. The patterns display some similarities with exp… more
Date: June 5, 1996
Creator: Kruecken, R.; Deleplanque, M. A.; Lee, I. Y. & Asztalos, S.
Partner: UNT Libraries Government Documents Department
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Characteristics of the 2.65 {mu}m atomic xenon laser

Description: The laser characteristics of the 2.65 {mu}m xenon laser transition are reviewed. Measured and extrapolated laser efficiency in nuclear pumped and electron beam pumped system is reported. Previous research has indicated that the reported power efficiency is between 0.1 and 2 percent.
Date: October 1, 1995
Creator: Hebner, G.A.
Partner: UNT Libraries Government Documents Department
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Energy dissipation by a longitudinal Raman process

Description: The concept of a longitudinal Raman process is introduced to encompass the indirect transmission of energy from slow electrons to nuclei through the reversible polarization of surrounding electrons. Experimental approaches are sought to assess this process quantitatively.
Date: July 1, 1994
Creator: Fano, U. & Inokuti, Mitio
Partner: UNT Libraries Government Documents Department
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Wavelength measurement of n = 3 - n' = 3 transitions in highly charged tungsten ions

Description: 3s{sub 1/2} - 3p{sub 3/2} and 3p{sub 1/2} - 3d{sub 3/2} transitions have been studied in potassium-like W{sup 55+} through neon-like W{sup 64}+ ions at the electron-beam ion trap facility in Livermore. The wavelengths of the lines have been measured in high resolution relative to well known reference lines from oxygen and nitrogen ions. Using the high-energy SuperEBIT electron-beam ion trap and an R = 44.3 m grazing-incidence soft x-ray spectrometer, the lines were observed with a cryogenic cha… more
Date: March 10, 2010
Creator: Clementson, J & Beiersdorfer, P
Partner: UNT Libraries Government Documents Department
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Reheating Metastable O'Raifeartaigh Models

Description: In theories with multiple vacua, reheating to a temperature greater than the height of a barrier can stimulate transitions from a desirable metastable vacuum to a lower energy state. We discuss the constraints this places on various theories and demonstrate that in a class of supersymmetric models this transition does not occur even for arbitrarily high reheating temperature.
Date: December 13, 2006
Creator: Craig, Nathaniel J.; /SLAC /Stanford U., ITP; Fox, Patrick J.; /LBL, Berkeley; Wacker, Jay G. & /SLAC /Stanford U., ITP
Partner: UNT Libraries Government Documents Department
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Search for Neutron to Anti-Neutron Transitions at HFIR/ORNL

Description: The transition of neutron to anti-neutron might be the first observed signal of the baryon instability long-awaited in Grand Unification models and required for the explanation of baryon asymmetry in the universe. A newly-proposed experiment to search for neutron-antineutron transitions at High Flux Isotope Reactor at Oak Ridge National Laboratory can improve the discovery potential by factor of {approximately} 1,000 relative to the existing limits. Further prospects of n -> n(overbar) searc… more
Date: October 22, 1998
Creator: Kamyshkov, Y.
Partner: UNT Libraries Government Documents Department
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Around the back-bend in an excited {sup 150}Gd superdeformed band

Description: The excited superdeformed band (band 5) in {sup 150}Gd has a discontinuity (back-bend) in the smooth variation of gamma-ray energy with spin at around 1 MeV. It has been established that the band also has a decay branch that is probably a continuation of band 5 below the back-bend. Gamma-rays have been identified which link band 5 with the yrast superdeformed band in {sup 150}Gd.
Date: December 1, 1996
Creator: Twin, P. J.; Ertuerk, S. & Beausang, C. W.
Partner: UNT Libraries Government Documents Department
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