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Application of generalized classical trajectories in nuclear physics

Description: A new semi-classical method, the so-called uniform semiclassical approximation, is described briefly and then applied to two nuclear physics problems. The basic features of this method are that the dynamics of the problem is treated completely classically (that is, one solves classical equations of motion), but the quantum mechanical superposition principle is retained by evaluating a phase along the classical trajectory and adding probability amplitudes for indistinguishable processes rather t… more
Date: September 1, 1975
Creator: Leser, H.M.
open access

Application of Soft X-Ray Appearance Potential Spectroscopy to Light Lanthanides, 4d Transition Metals, and Insulators

Description: Evaporated films of La, Ce, Yb, Y, Ag--Mn(5 percent), KCl, MnF$sub 2$, CsCl and LaF$sub 3$ were studied using the soft x-ray appearance potential spectroscopy (SXAPS) technique. Studies were also made of bulk polycrystalline samples of Y, Zr, Nb, and Mo. The results are discussed in terms of existing SXAPS theories. Several similarities between soft x-ray absorption (SXA) data and the SXAPS results are discussed, and it is shown that the SXA data can aid in the interpretation of SXAPS spectra w… more
Date: October 1, 1975
Creator: Smith, R. J.
open access

Applications of time-differential perturbed angular correlations to the study of solids

Description: Time-differential perturbed angular correlation techniques were applied to a systematic study of insulating antiferromagnets and rare-earth intermetallic alloys doped with either /sup 111m/Cd or $sup 111$In. The internal magnetic fields and electric field gradients at the radioactive nucleus are deduced from the experimentally measured perturbation factors. The analysis of fluoride, chloride, oxide, and sulfide data shows the systematic variation of the observed supertransferred hyperfine field… more
Date: June 1, 1975
Creator: Schwartz, G.P.
open access

CARBON-13 NMR STUDIES OF LIQUID CRYSTALS

Description: High resolution, proton decoupled {sup 13}C nmr are observed for a series of neat nematic liquid crystals, the p-alkoxyazoxybenzenes, and a smectic-A liquid crystal, diethylazoxydibenzoate in a magnetic field of 23 kG. The (uniaxial) order parameters S = <P{sub 2}(cos{theta})> are found to be about 0.4 and 0.9 for the nematic and smectic-A phase respectively at the clearing points. The order parameter increases with decreasing temperature in the nematic phase but is constant, or nearly so… more
Date: June 1, 1975
Creator: Allison, Stuart
open access

Coherence in multilevel systems

Description: Mathematical descriptions of an excited state multilevel system are developed to include progressively the effects of coherent coupling, feeding, decay and relaxation, and the expressions are illustrated with several pulse coherence experiments utilizing zero field optically detected magnetic resonance of excited triplet states. A new method is described in which the time development of the coherent components in a multilevel system is monitored by using an observable that can measure only rela… more
Date: July 1, 1975
Creator: Breiland, W.G.
open access

Comparison between phase shift derived and exactly calculated nucleon--nucleon interaction matrix elements. [Tables]

Description: A comparison is made between matrix elements calculated using the uncoupled channel Sussex approach to second order in DWBA and matrix elements calculated using a square well potential. The square well potential illustrated the problem of the determining parameter independence balanced with the concept of phase shift difference. The supersoft core potential was used to discuss the systematics of the Sussex approach as a function of angular momentum as well as the relation between Sussex generat… more
Date: January 1, 1975
Creator: Gregersen, A. W.
open access

Cooling of interstellar formaldehyde by collision with helium: an accurate quantum mechanical calculation

Description: In order to test a collisional pumping model as a mechanism for cooling the 6 cm and 2 cm doublets of interstellar formaldehyde, a quantum mechanical scattering calculation is performed. To obtain the intermolecular interaction between H$sub 2$CO($sup 1$A$sub 1$) and He($sup 1$S) two calculations are performed, a Hartree-Fock (HF) potential surface and a configuration interaction (CI) surface. A basis set of better than ''triple zeta plus polarization'' quality is used to compute the HF portion… more
Date: August 1, 1975
Creator: Garrison, B. J.
open access

Coupled MHD-Monte Carlo transport model for dense plasmas

Description: A two-dimensional, two fluid model of the MHD equations has been coupled to a Monte Carlo transport model of high energy, non-Maxwellian ions. The MHD part of the model assumes complete ionization and includes a perfect gas law for a scalar pressure, a tensor artificial viscosity, electron and ion thermal conduction, electron-ion coupling, and a radiation loss term. A simple Ohm's Law is used with a B/sub theta/ magnetic field. The MHD equations were solved in Lagrangian coordinates. The conser… more
Date: June 1, 1975
Creator: Chandler, W.P.
open access

Creep rupture properties of laves phase strengthened Fe--Ta--Cr--W and Fe-- Ta--Cr--W--Mo alloys

Description: A small addition of tungsten (0.5 at. percent) was shown to have an effect similar to that of molybdenum on the phase transformation characteristics of alloy Ta7Cr (with a nominal composition of 1 at. percent Ta, 7 at. percent Cr, balance Fe). The existence of time-temperature dependent transformation behavior in alloy Ta7Cr0.5W was confirmed. The effect of spheroidization time and temperature on creep strength was determined. In addition, effect of mechanical processing prior to aging, on cree… more
Date: December 1, 1975
Creator: Singh, S.
open access

Determination of the K/sub L/$sup 0$ $Yields$ $pi$$sup -$$mu$$sup +$$nu$/ sub $mu$/ form factor xi(q$sup 2$) by muon polarization measurements

Description: The polarization of the muon in the decay K$sup 0$/sub L/ $Yields$ $pi$$sup -$$mu$$sup +$$nu$/sub $mu$/ was measured as a function of q$sup 2$, the four-momentum transferred to the lepton pair. The kinematic information was used to compute the polarization expected on the basis of various assumed values of the form factor xi(q$sup 2$). By comparing the interpolated curve of the polarization as a function of xi(q$sup 2$) to the experimentally measured polarization, one has determined xi(q$sup 2$… more
Date: September 1, 1975
Creator: Shen, G.
open access

Deuteron nuclear magnetic resonance investigation of LaNi$sub 5$D/sub x/ compounds

Description: The $sup 2$D quadrupole interaction was observable in all the samples of LaNi$sub 5$D/sub x/ up to a critical temperature T/sub c/ at which the intensity of the quadrupole interaction spectrum disappeared and only a narrow unsplit line remained. The critical temperatures were 360$sup 0$K for the x = 3.6 sample and 380$sup 0$K for the x = 5.7, 6.7 samples. Based on preliminary electric field gradient (EFG) calculations, it appears likely that several quadrupole interactions are being observed fr… more
Date: October 1, 1975
Creator: Nelson, S.O.
open access

Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

Description: The effect of free-particle collisions in simple ''knockout'' reactions of the form (a,aN) and in more complex nuclear reactions of the form (a,X) was investigated by using protons and pions. Cross sections for the $sup 48$Ti(p,2p)$sup 47$Sc and the $sup 74$Ge(p,2p)$sup 73$Ga reactions were measured from 0.3 to 4.6 GeV incident energy. The results indicate a rise in (p,2p) cross section for each reaction of about (25 +- 3) percent between the energies 0.3 and 1.0 GeV, and are correlated to a la… more
Date: July 1, 1975
Creator: Jacob, N.P. Jr.
open access

Effects of temperature and microstructure on the elastic properties of selected Eu$sub 2$O$sub 3$-HfO$sub 2$ compositions

Description: Europium oxide is presently being tested for use as the control material in future nuclear power reactors. Elastic properties of europia and selected europia-rich compositions of the europia-hafnia system were investigated. The sonic technique was employed to measure elastic moduli from room temperature to 1500$sup 0$C. Sintered monoclinic europia specimens were found to have uncommonly low room temperature moduli values and to exhibit hysteresis between heating and cooling curves because of th… more
Date: October 1, 1975
Creator: Suchomel, R.R.
open access

Electron microscopy studies of ion implanted silicon

Description: The nature of defects resulting from the implantation of phosphorous ions into doped silicon and a model of how they form are reported. This involved an electron microscope study of the crystallographic defects (in the 300A size range in concentration of 10$sup 15$/cm$sup 3$) that form upon annealing. Images formed by these crystallographic defects are complex and that nonconventional imaging techniques are required for their characterization. The images of these small defects (about 300A) are … more
Date: November 1, 1975
Creator: Seshan, K.
open access

Far infrared spectroscopy of solids. I. Impurity states in Al$sub 2$O$sub 3$. II. Electron-hole droplets in Ge

Description: Far infrared Fourier transform spectroscopy was used to study the low lying vibronic states of Mn$sup 3+$ in Al$sub 2$O$sub 3$ and the plasma absorption of electron-hole droplets in Ge. The transmission of Mn-doped samples of Al$sub 2$O$sub 3$ was measured in the frequency range from 3 to 30 cm$sup -1$ in applied magnetic fields up to 50 kG. Absorption lines were observed due to both ground and excited state transitions. Polarization measurements established that these absorption lines were due… more
Date: September 12, 1975
Creator: Aurbauch, R.L.
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