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CreatorTitleDescriptionSubjectDate
76 Ailion, David CharlesNMR methods for identifying and studying diffusion of different spin species in heteronuclear systemsWe introduce a new dipolar relaxation lime TU)' which characterizes the spin-lattice relaxation of secular dipolar interactions in the presence of a large rf field. Measurements of T]D' are particularly useful for studying slow atomic motions in muitispin systems, since such measurements enable us ...NMR; Nuclear magnetic resonance; Nuclear-spin species; Diffusion; Molecular rotations1978
77 DeTar, CarletonHadronic deformation energy. I. Quark-antiquark separationThe MIT bag model for hadrons is treated in the static cavity approximation in three dimensions with a definite quark number. The energy of the system is computed to second order in the gluon coupling. A constrained variational method is described which permits the calculation of the energy as a f...Bag models; Quark bag; Deformation energy; Antiquarks; Gluon coupling; Quark energies; Gluon energies1978-01
78 DeTar, CarletonHadronic deformation energy. II. Two-nucleon interactionThe MIT bag model for hadrons is treated in the static cavity approximation. The adiabatic deformation of a six-quark hadron with quantum numbers of the deuteron is studied in a configuration which permits the separation of two triplets with quantum numbers of the neutron and proton. The energy of...Bag models; Quark bag; Deformation energy; Gluon coupling; Two-nucleon problem; Nucleons; Self-energy1978-01
79 Mattis, Daniel C.Solution of multiple scattering by finite iterationWe propose an iterative nonlinear solution to the general potential scattering problem in quantum mechanics. It is illustrated by the case of N2 localized scatterers of arbitrary strengths Vj located at arbitrary points Rj in an infinite lattice, for which we obtain the complete set of bound and sca...Bound states; Eigenstates1978-01
80 Vardeny, Zeev ValentineSpecific heats and lattice dynamics of cuprous halidesThe specific heats Cp(T) of CuCl, CuBr, and Cul were measured by the adiabatic calorimetric technique. The corresponding Debye temperature for each crystal is given and a comparison between the results is drawn. The room-temperature phonon dispersion relations for these cystals are fitted by a nine...Cuprous halides; CuBr; CuCl; CuI1978-10
81 Mattis, Daniel C.Eigenstates of excitons near a surfaceThe exact eigenstates and energies of an electron and a hole of equal effective masses, with an attractive δ-function interaction and hard-wall repulsion at the surfaces of a solid, are classified and obtained explicitly for a solid of arbitrary thickness. Both bound and scattering states of the e...Eigenstates; Frenkel excitons1978-10
82 Ailion, David CharlesNuclear magnetic resonance study of diffusion of bound and free fluorine interstitials in alkaline earth fluorides doped with trivalent impuritiesWhen alkaline-earth fluorides are doped with trivalent impurities, interstitial fluorines are created to maintain charge neutrality. We have performed NMR dipolar-energy relaxation measurements over a wide temperature range and have observed the diffusion of both free and locally bound fluorine inte...Diffusion; Motion; Crystals; NMR; Fluorine1979
83 Ailion, David CharlesZeeman-quadrupole cross relaxation between two nuclear spin speciesWe derive an expression for the rate T / s ' of the cross relaxation between the Zeeman splitting of one nuclear spin species (/ spins, I = 1/2) and the quadrupole splitting of another spin species ( 5 spins, S > 1/2) via the IS dipolar interaction. We calculate T , s for the case of CFCL2-CFCL2 (/ ...Spin species; Spin-lattice relaxation1979
84 Ailion, David CharlesNMR observations of molecular motions and Zeeman-quadrupole cross relaxation in 1,2- difluorotetrachloroethaneWe report measurements of "F NMR relaxation times Tu Tlf, TID, and T2 in the plastic crystal CFCL2-CFCL2 . From the data near the melting point, we obtain the jump time for translational selfdiffusion. At lower temperatures, we observe on the cold side of the T, and Tif minima an unusual field depe...NMR; Nuclear magnetic resonance; Order-disorder; Diffusion1979
85 Symko, Orest GeorgeCalibration of SQUID magnetometer for dilute alloy studiesA SQUID magnetometer used in the study of dilute magnetic alloys or other weak magnetic systems can be calibrated by using the nuclear paramagnetism of aluminum metal. This material is useful as a calibration standard since magnetic impurities such as Fe and Mn form no local moment. This calibration...SQUID magnetometer1979
86 Vardeny, Zeev ValentinePhonon anomalies in Cu halidesA great number of the observed phonon anomalies in the zinc-blende phase of Cu-halide crystals are explained by means of a dynamical model. It is assumed that a Cu ion populates four equivalent off-center sites or its ideal position. The off-center Cu+ population is temperature and pressure dependen...Phonon anomalies; Cu-halide crystals; Cuprous halides1979-03
87 Vardeny, Zeev ValentineDisorder-induced TA Raman lines in mixed Cu-halide crystalsThe Raman spectra of CuClxBr1=x and CuBrxI1=x solid solutions are shown to contain extremely intense disorder-induced first-order TA phonons. The intensity of these lines is a function of the concentration x, and is highest in CuCl0.6oBr0.40. The TA spectrum, well resolved at low temperature, fits...Cuprous halides; CuBr; CuCl; CuI; mixed Cu-halide crystals1979-03
88 DeTar, CarletonTensor component of the two-nucleon interaction in the quark-bag modelA previously developed method for computing the interaction energy of the two-nucleon system at short distances in the static MIT bag model of confined quarks is extended to all isospin and spin channels available to the two-nucleon interaction. The present study is restricted to spherical geometri...Bag models; Quark bag; Nucleons; Deformation energy1979-03
89 Sokolsky, PierreSearch for new particles at the alternating-gradient-synchrotron beam dumpThis paper presents results of a beam-dump experiment performed at the Brookhaven alternating-gradient synchrotron to search for prompt sources of neutrinos and axionlike particles. We observe no excess of vµ or events, and no excess in neutral-current events over that expected from neutrinos from ...1979-05
90 Mattis, Daniel C.Molecular-field theory with correlationsWe derive an improved molecular-field theory for spins 1/2 from first principles. Formulas are obtained for use in cases when the fields, bonds, or occupation of the sites are random variables.Molecular-field theory; Spin glasses1979-05
91 Mattis, Daniel C.Ground-state symmetry in XY model of magnetismNumerical studies by Betts and Oitmaa have led those authors to conjecture that in the XY model the ground-state magnetization Mz is zero. This is a model of spins on a lattice with interactions - J(SnxSmx+SnySmy), that can also describe a hard-sphere boson fluid. In the present note I prove the c...Ground state; Magnetization; Bipartite lattice1979-06
92 Mattis, Daniel C.Soluble Ising model in 2+1/N dimensions and XY model in 1+1/N dimensionsThe XY model is exactly soluble on a comblike structure, by means of a modified Jordan-Wigner transformation. This method is used to reduce the transfer matrix of the Ising model, on planes which are joined to each other at one edge, to a soluble canonical form.Jordan-Wigner transformation1979-07
93 Ailion, David CharlesNMR determination of structural domains in NaCNMeasurements of the first- and second-order quadrupole energy-level shifts are performed in a 23Na NMR experiment in a single crystal of NaCN. Twelve orthorhombic domains are found below the phase transition at 15°C. They consist of six pairs of domains with each one oriented by an angle 2/3 rel...NMR; Nuclear magnetic resonance; Crystals; Structural domains1980
94 Vardeny, Zeev ValentinePhonon-polaritons in Cu halides: anomalies and their temperature dependenceThe polariton Raman spectra of CuCl, CuBr, and Cul crystals are studied at various temperatures of their zinc-blende phase. Two polar modes are proven to exist in CuCl at room temperature and below; their oscillator-strength ratio changes with temperature and follows the temperature dependence of ...Cuprous halides; CuBr; CuCl; CuI; Phonon anomalies; Temperature dependence; Zinc blende phase1980-03
95 Vardeny, Zeev ValentineOptical studies of excess carrier recombination in α-Si:H: evidence of dispersive diffusionRelaxation of photoinduced optical absorption following pulsed laser excitation was measured between 0.5 pis and 10 ms in doped and undoped a-Si:H as a function of temperature. The recombination was found to be bimolecular diffusion limited. The diffusion coefficient of the excess carriers is time ...Hydrogenated amorphous silicon; a-Si:H; Excess carrier recombination; Dispersive diffusion1980-05
96 Mattis, Daniel C.Improved Landau-Ginzburg equation near surfaces of solidsWe study the order parameter near the surface for an Ising model. Applications to the lattice gas, alloy problem, and ferromagnetism are noted. Away from Tc our equations differ from the Landau-Ginzburg results due to an additional nonlinear, term which can substantially affect the order parameter...Landau-Ginzburg equation; Boundary conditions1980-12
97 Mattis, Daniel C.; Sutherland, BillStrange solutions to field theories in one spatial dimensionMany models of interacting particles rely heavily for their solution on restriction to one-dimensional motion and a linearized kinetic energy. We examine this in detail, and find that the linearization can lead to patently strange and possible spurious solutions in first quantization. The usual, co...Eigenstates; Field theories1981
98 Ailion, David CharlesNature of Ag+ self-diffusion in AgFMeasurements of the nuclear magnetic resonance (NMR) dipolar relaxation times T w and T i (51°) have been made on the 1 9 F resonance in AgF powder over the temperature range 60-300 K. Also the technique of Stokes and Ailion for detecting the diffusion of weakly magnetic spins has been verified f...NMR; Nuclear magnetic resonance; Diffusion; Ionic conductivity1981
99 Vardeny, Zeev ValentineRecombination kinetics in ?-Si:HMort et al.1 reinterpreted our data on the relaxation of photoinduced absorption (PA) in a-Si:H. 2 We want to show that the proposed interpretation contradicts one basic feature of the data while our original interpretation is in good agreement with experiment.Hydrogenated amorphous silicon; a-Si:H; Recombination kinetics; Photoinduced absorption; Decay; Relaxation1981
100 Vardeny, Zeev ValentineOptical picosecond studies of carrier thermalization in amorphous siliconThermalization of photogenerated hot carriers in a-Si, a-Si:H and a-Si:H:F was studied using the pump and probe method with subpicosecond resolution. The process is optically observable because the absorption cross-section of the hot carriers depends on their excess energy. It was found that the en...Carrier thermalization; Amorphous silicon; Frohlich interaction1981
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