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Filters: Format Medium: "application/pdf" Journal Title: "Physical Review B" Collection: "ir_uspace"
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1 Liu, Feng(BAl12)Cs: a cluster-assembled solidFirst-principles calculations on the geometry and stability of AlnBm clusters have been carried out to examine the effect of size, composition, and electronic-shell filling on their relative stability. It is shown that although Al and B are both trivalent, a BAl12 cluster is more stable than an Al1...First-principles calculations; (BAl12)Cs; Cluster-assembled; AlnBm clusters1997-06
2 Ailion, David Charles109Ag NMR investigation of atomic motions in the incommensurate and paraelectric phases of proustite (Ag3AsS3)109Ag NMR line shape, T1 , Hahn spin echo, and Carr-Purcell-Meiboom-Gill ~CPMG! spin-echo measurements were performed in proustite (Ag3AsS3) between 420 and 47 K in order to understand the role of atomic motions in phase transitions in a system containing an incommensurate phase. These measurements ...NMR; Atomic motion; Proustitie; Phase transitions; Line shape2000
3 Ailion, David Charles14N study of the role of N-D---O bonds in the deuteron glass transition14N spin-lattice relaxation-time measurements in Rb0.28(ND4)0.72D2PO4 provide direct evidence for the fast exchange averaging of the "long" and "short" N-D---O hydrogen bonds between the ND4 group and the four surrounding PO4 groups. This exchange and the associated distortion of the ND4 tetrahedron...NMR; Hydrogen bonds; Spin-lattice; Relaxation-time; Deuteron glass1999
4 Miller, Joel Steven1H NMR investigation of the magnetic spin configuration in the molecule-based ferrimagnet [MnTFPP][TCNE]1H NMR line-shape measurements have been performed in the linear chain molecule-based ferrimagnet [MnTFPP][TCNE].xPhMe (TFPP=tetrakis(4-fluorophenyl)porphinato; TCNE=tetracyanoethylene) as a function of temperature. Hyperfine shifts of opposite sign were observed indicating the presence of two oppo...Magnetization; Magnets; Paramagnetic2002
5 Ailion, David Charles31P NMR spin-lattice relaxation: structural glass dynamics in Rb1-x(ND4)xD2PO4We performed 3 1P NMR measurements of the temperature-dependent spin-lattice relaxation time in several mixed single crystals of Rbi_x(ND4 ) xD2P04 [DRADP] having different ammonium concentration x (x =0.22, 0.44, 0.78) as well as in three pure single crystals (ND4)D2P04 [DADP], (NH4)H2P04 [ADP], an...NMR; Spin-lattice; Relaxation; Crystals; Glass; Spin-glass1993
6 Ailion, David Charles; Blinc, Robert35Cl spin-lattice relaxation in incommensurate bis(4-chlorophenyl)sulfoneThe 35C1 nuclear-quadrupole-resonance (NQR) spin-lattice relaxation rate in incommensurate bis(4- chlorophenyl)sulfone (BCPS) is determined by Raman processes below 60 K and by direct one-phonon processes above 60 K. The variation of the 35C1 spin-lattice relaxation rate over the incommensurate NQR...35Cl; Incommensurate bis(4-chlorophenyl)sulfone; Raman processes; NQR; Incommensurate systems1995-01
7 Ailion, David Charles79Br nuclear-quadrupole-resonance lineshape and Raman-induced spin-lattice relaxation in the incommensurate phase of β- ThBr4We performed 7 9Br nuclear-quadrupole-resonance (NQR) line-shape and spin-lattice relaxation time measurements in the incommensurate (D system j8-ThBr4 over the temperature range 293-2.5 K. In addition, we extended the theory of the effects of Raman processes on amplitudon and phason spin-lattice re...Spin-lattice; NQR; Raman process; Line shape; Phason gap; Incommensurate systems1989
8 Ailion, David Charles93Nb NMR in the imcommensurate and quasi-commensurate phases of barium sodium niobateNMR spectra have been measured for the quadrupole perturbed 1/2 -1/2 transition of 9 3Nb in barium sodium niobate (BSN) between 300 and 650 K. The spectra are inhomogeneously broadened in the incommensurate (/) phase between T7 = 580 K and r c = 540 K as well as in the quasicommensurate (QC) phase ...NMR; Spectra; Barium sodium niobate; Line shapes1994
9 Vardeny, Zeev ValentineAbsorption-detected magnetic-resonance studies of photoexcitations in conjugated-polymer/C60 compositesPhotoexcitations in poly[2-methoxy-5-(2'-ethyl-hexyloxy -p-phenylene vinylene] (MEH-PPV) and composites of MEH-PPV and C60 (MEH-PPV/C60) were studied by photoinduced absorption and absorptiondetected magnetic-resonance spectroscopies. We report direct evidence that the prominent triplet photoexci...Photoexcitations; Conjugated-polymer/C60 composites; Triplet photoexcitations1996-02
10 Vardeny, Zeev Valentine; Ehrenfreund, Eitan A.Amplitude and phase modes in trans-polyacetylene: resonant Raman scattering and induced infrared activityThe resonant Raman scattering (RRS) from the three Ag modes of trans-polyacetylene and the charged-induced ir modes are analyzed with use of the amplitude- and phase-mode theories. It is shown that the observed phonon frequencies and the relative intensities of all modes obtained at various laser ex...Induced infrared activity; Ag modes; Amplitude modes; Phase modes; Trans-polyacetylene1987-07
11 Vardeny, Zeev ValentineAnomalous optical and ESR properties of doped polydiethynylsilanesThe optical, transport, and ESR properties of soluble conducting four-membered polydiethynylsilane heterocycles are described. The undoped one-dimensional gap is 2.0 eV in both films and solutions; no photoluminescence is observed. I2 doping induces a single absorption band at -1.05 eV in solutions...Polydiethynylsilane; Doped polydiethynylsilanes1991-09
12 Wu, Yong-ShiAnyons on a torus: braid group, Aharonov-Bohm period, and numerical studyWe present a careful construction of anyons on a torus starting with the braid-group analysis. The rules of Wen, Dagotto, and Fradkin for putting anyons on a torus are reproduced with some minor improvements. The existence of noncontractible loops leads to braid-group representations characterized n...Braid group; Magnetic flux1991-05
13 Vardeny, Zeev Valentine; Ehrenfreund, Eitan A.Apparent vibrational side bands in rr-conjugated systems: the case of distyrylbenzeneThe photoluminescence sPLd spectra of dilute solution and single crystals of distyrylbenzene show unique temperature-dependent vibronic structures. The characteristic single frequency progression at high temperatures is modulated by a low-frequency progression series at low temperatures. None of th...pi-conjugated systems; Distyrylbenzene; Vibrational side-bands; Vibronic structures; DSB2005-02
14 Mattis, Daniel C.Application of tridiagonalization to the many-body problem. II. Finite TIn a previous paper of the same title, we obtained the ground-state energy of a magnetic (Wolff-model) impurity in a nonmagnetic metal. In the present Brief Report, we calculate the impurity's contribution to the density of states and heat capacity of the metal at low temperatures. Here, the Lancz...Ground-state energy; Tridiagonalization; Magnetic impurity; Nonmagnetic metals; Heat capacity1984-06
15 Liu, FengBending of nanoscale ultrathin substrates by growth of strained thin films and islandsMechanical bending is ubiquitous in heteroepitaxial growth of thin films where the strained growing film applies effectively an "external" stress to bend the substrate. Conventionally, when the deposited film is much thinner than the substrate, the bending increases linearly with increasing film th...Nanoscale ultrathin substrates; Strained thin films; Islands; Heteroepitaxial growth; Si substrate; Ge film2005-08
16 Wu, Yong-ShiBraid group and anyons on a cylinderIn this paper we present a careful reexamination of anyons on a cylinder (or annulus), starting from the braid-group analysis. Proper attention is paid to the topological features arising from the existence of noncontractible loops. The rule for putting anyons on a square lattice has to be modified ...Braid group; Annulus1991-02
17 Symko, Orest GeorgeChaos in long Josephson junctions without external rf driving forceSimulations of long Josephson junctions in an external magnetic field show a variety of chaotic behaviors. They consist of period-doubling bifurcation, intermittency between and within Fiske steps, and quasiperiodic motion at Fiske steps. A physical explanation for the chaotic behavior is presented....Fiske steps; Chaos; Chaotic behaviors1990-09
18 Vardeny, Zeev ValentineCoherent umklapp scattering of light from disordered photonic crystalsA theoretical study of the coherent light scattering from disordered photonic crystals is presented. In addition to the conventional enhancement of the reflected light intensity into the backscattering direction, the so-called coherent backscattering (CBS), the periodic modulation of the dielectri...Coherent umklapp scattering; Disordered photonic crystals; Coherent backscattering; Bragg2001-05
19 Vardeny, Zeev Valentine; Ehrenfreund, Eitan A.Comment on "Frequency response and origin of the spin-½ photoluminescence-detected magnetic resonance in a ∏-conjugated polymerIn a recent paper, Segal et al. [Phys. Rev. B 71, 245201 (2005)] advanced a new explanation for the dynamics of spin-1/2 photoluminescence-detected magnetic resonance (PLDMR) in films of a rr-conjugated polymer, namely, a soluble derivative of poly(phenylene-vinylene) (MEH-PPV), using a model [dubbe...Photoluminescence-detected magnetic resonance; PLDMR; pi-conjugated polymers; Poly(phenylene-vinylene); MEH-PPV2007-06
20 Mattis, Daniel C.Comment on "Ground-state properties of a spin-1 antiferromagnetic chainBotet and Jullien [Phys. Rev. B 27, 613 (1983)] and Botet, Jullien, and Kolb [Phys. Rev. B 28, 3914 (1983)] performed a finite-size scaling analysis of the spin-1 antiferromagnetic Heisenberg-Ising chain. Their work was criticized by Bonner and Mtiller [Phys. Rev. B 29, 5216 (1984)] on the grounds...Antiferromagnets; Ground-state; Ising chain; Energy gap1985-04
21 Scarpulla, MichaelCompensation-dependent in-plane magnetization reversal processes in Ga1-xMnxP1-ySyWe report the effect of dilute alloying of the anion sublattice with S on the in-plane uniaxial magnetic anisotropy and magnetization reversal process in Ga1−xMnxP as measured by both ferromagnetic resonance (FMR) spectroscopy and superconducting quantum interference device (SQUID) magnetometry. ...Ferromagnetic semiconductors; Nonmagnetic compensation2008-12
22 Liu, FengComputational designing of carbon nanotube electromechanical pressure sensorsWe investigate electronic transport properties of single-walled carbon nanotubes (SWNT's) under hydrostatic pressure, using first-principles quantum transport calculations aided by molecular-dynamics simulation and continuum mechanics analysis. We demonstrate a pressure-induced metal-to-semiconduc...Carbon nanotubes; Computational designing; Pressure sensors; Electronic transport2004-04
23 Vardeny, Zeev ValentineConfined and delocalized polarons in ∏-conjugated oligomers and polymers: a study of the effective conjugation lengthWe studied optical absorption of polarons in ∏-conjugated oligomers and polymers using the photoinduced absorption technique as well as chemical doping spectra from the literature. We find that the photon energy of the polaron low-energy transition obeys a relationship that depends only on the oli...Confined polarons; Delocalized polarons; pi-conjugated oligomers; pi-conjugated polymers; Effective conjugation length2004-06
24 Lupton, John MarkControl of mobility in molecular organic semiconductors by dendrimer generationConjugated dendrimers are of interest as novel materials for light-emitting diodes. They consist of a luminescent chromophore at the core with highly branched conjugated dendron sidegroups. In these materials, light emission occurs from the core and is independent of generation. The dendron branchin...Dendrimer generation; Dendron branching; Charge transport; Mobility2001-03
25 Vardeny, Zeev ValentineCooperative and stimulated emission in poly(p-phenylene-vinylene) thin films and solutionsWe discuss cooperative and stimulated emissions and separate their respective contributions to the emission spectral narrowing in thin films and solutions of poly(p-phenylene-vinylene) derivatives. Whereas cooperative radiation is favored in films with poor optical confinement, directional stimula...pi-conjugated polymers; PPV; Spectral narrowing1998-04
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