bluuebunny/crossref_metadata_2025 huggingface dataset:
The Quantum-Mechanical Treatment of Molecules by the Method of Spin Valence
Authors: Wheland G. W.
Published: November 2004

The method of spin valence, developed by Born, Heitler, Rumer and Weyl for the treatment of molecular systems, becomes completely equivalent to the Slater method if the bonding forces are considered to be exerted between individual orbitals, and not between entire atoms in definite spectroscopic states. This change in the point of view eliminates several difficulties which were formerly present in the method (e.g., the obscuring of the directional properties of the valence bonds). The secular equation, for which a simplified derivation is given, is of quite a different form from the Slater equation, and the problem of its solution is considered in some detail. In addition to the rigorous methods, several approximate methods are given, of which two (applicable to unsaturated and aromatic hydrocarbons) do not require that the secular equation be set up at all. The method of spin valence is found to be more convenient than the Slater method for the treatment of systems of high multiplicity. Finally, the extension to cases of orbital, as well as spin degeneracy is briefly outlined.
The Raman Spectrum of Sulphuric Acid
Authors: Bell Raymond M. , Jeppesen Myron A.
Published: November 2004

A study was made of the Raman spectrum of sulphuric acid at concentrations varying every five percent from 100 to 5 percent by volume. A dispersion of 10A/mm at 4200A and 15A/mm at 4500A was used. Eight lines were found, which varied gradually in frequency, width, and intensity with changing concentration. Their frequency ranges are 408–432, 561–596, 913–895, 970–973, 980–983, 1031–1051, 1142–1174, 1216–1236, 1352–1332. A gradual change in frequency with concentration was found for a number of the lines. The measurements were checked with a microphotometer.
Raman Spectra of Some Molecules of the Pentatomic Type
Authors: Rank D. H. , Bordner E. R.
Published: November 2004

Raman spectra of a number of organic compounds containing a neopentyl group have been obtained. Among these is tetramethyl methane-d1. The spectrum of this compound shows the various types of isotope effects to be expected for a polyatomic molecule. It is also apparent from the spectrum that the vibrations of tetramethylmethane-d1 are less degenerate than the vibrations of tetramethylmethane. The spectrum of tetramethylsilicon has 5 lines in the internal vibration spectrum. The explanation for the existence of this extra line is probably the same as that given by Fermi in the case of CCl4.
Scattering of X-Rays by Polyatomic Liquids. n-Heptane
Authors: Pierce W. C.
Published: November 2004

A Fourier integral analysis of Katzoff's data for the x-ray scattering of n-heptane gives not only the arrangement of molecules in the liquid, but also the most probable distances within the single molecule. It is shown that the molecule consists of a zigzag carbon chain. Adjacent molecules are somewhat oriented and increase in temperature makes a more random condition. The Fourier integral theorem is shown to be valid even though the function for which it is used does not converge within the limits of the data. The distribution function is used to calculate the intensity, giving a fair agreement with the experimental values.
The Far Ultraviolet Absorption Spectra of Formaldehyde and the Alkyl Derivatives of H2O and H2S
Authors: Price W. C.
Published: November 2004

The absorption spectra of formaldehyde and of compounds of the type HOH, ROH, ROR and HSH, RSH, RSR have been observed in the region 2300–1000A. An analysis of the spectrum of formaldehyde yields a value of 10.83±0.01 volts for the first ionization potential of the C=O bond and about 164 Cal./mole for the strength of this bond. The spectra of the alkyl derivatives of H2S are all shown to be shifted to the long wavelength region relative to those of H2O. Rough estimates of their ionization potentials are given and the influence of dipole moment on the ultraviolet absorption spectra and ionization potentials of polyatomic molecules is discussed.
The Kinetics of the Decomposition of Gaseous Glyoxal
Authors: Steacie E. W. R. , Hatcher W. H. , Horwood J. F.
Published: November 2004

The decomposition of gaseous glyoxal has been investigated from 410° to 450°C. The reaction is homogeneous and first order. Considerable carbon and tar is deposited, however, and the results are erratic. The following three reactions occur to about the same extent: CHO–CHO=2 CO+H2,CHO   CHO=C+CO+H2O,CHO   CHO=1n (CHO–CHO)n.The results are discussed from the point of view of the occurrence of glyoxal as an intermediate in the oxidation of acetylene.
Orientation Effects in Bimolecular Ionic Reactions
Authors: Sturtevant Julian M.
Published: November 2004

It is shown on the basis of accepted views concerning second order ionic reactions in solution that the variation with concentration of the electrostatic orientation effects in such a reaction arising from the lack of symmetry of a spheroidal ion is negligible in dilute solution. Deviations from Brönsted's law must be attributed to other causes.
Statistical Mechanics of Fluid Mixtures
Authors: Kirkwood John G.
Published: November 2004

Expressions for the chemical potentials of the components of gas mixtures and liquid solutions are obtained in terms of relatively simple integrals in the configuration spaces of molecular pairs. The molecular pair distribution functions appearing in these integrals are investigated in some detail, in their dependence upon the composition and density of the fluid. The equation of state of a real gas mixture is discussed, and an approximate molecular pair distribution function, typical of dense fluids, is calculated. Applications of the method to the theory of solutions will be the subject of a later article.
On the Speed of Sublimation and Condensation
Authors: Herzfeld K. F.
Published: November 2004

It has been assumed that in the simplest case every atom that hits a crystal surface of the same material condenses. The corresponding speed of sublimation had been calculated theoretically. The formula for the equilibrium pressure is changed in the case of atoms, if the electron weight in the gaseous state is different from the solid state. The influence of this fact on the speed of sublimation is discussed in the first part of the paper and it is shown that for true metals the speed of sublimation is probably increased, while for non-metals a reflection coefficient exists. For molecules the equilibrium pressure is higher than for atoms because in sublimation there is a transition from a limited oscillation of the axes to free rotation. It is made plausible that this results in an increased speed of sublimation but a finite reflection coefficient might also occur.
The Mercury Photosensitized Polymerization of Acetylene and Acetylene-d2
Authors: Jungers Joseph C. , Taylor Hugh S.
Published: November 2004

The mercury photosensitized polymerization of acetylene and acetylene-d2 has been studied. The rate of reaction is 30 percent greater with acetylene than with the deuterocompound, over the whole pressure range investigated. At low pressures, the rate varies as the acetylene pressures but in the pressure range 0.7–4 cm the initial rate of polymerization is practically independent of the acetylene pressure and determined by the intensity of absorbed resonance radiation. The quantum yield is approximately 6.5 for acetylene and 5 for acetylene-d2 lower than the yield for acetylene at the same temperature in the photochemical reaction (λ∼2000A). The results are also compared with corresponding studies of the polymerization process under the influence of α-particles.
The Orientation of Unsymmetrical Molecules at Interfaces
Authors: Bauer S. H. , Pollack A.
Published: November 2004

A function giving the distribution of the angles of orientation of the molecular axes from the normal to the interface can be obtained if one makes use of a number of special assumptions regarding the forces of orientation. This is compared with the distribution calculated on assuming an extreme form of Langmuir's principle of independent surface action. The importance of having such a function is pointed out.
The Conductance of Potassium Chloride and of Hydrochloric-Deuterochloric Acid H2O—D2O Mixtures. The Viscosity of H2O—D2O
Authors: Baker Weldon N. , La Mer Victor K.
Published: November 2004

The conductances of 0.01 normal solutions of potassium chloride and of hydrochloric-deuterochloric acid in H2O—D2O mixtures, and the viscosities of H2O—D2O mixtures, have been investigated as a function of D2O concentration at 25°C. The viscosity of D2O is 23 percent greater, the conductance of potassium chloride in D2O is 17 percent less, and the conductance of deuterochloric acid in D2O is 26 percent less, than the corresponding values in H2O. The viscosity, and the conductance of potassium chloride solutions and of hydrochloric-deuterochloric acid solutions show a maximum deviation of 0.4, 0.8 and 5.4 percent of the total values, respectively, from linearity. The decreased conductance of potassium chloride solutions in D2O is due mainly to the increased viscosity of the solvent. The marked deviation from linearity of the hydrochloric-deuterochloric acid curve is interpreted on the basis of a statistical correction to the proton exchange mechanism for the mobilities of H3O+ and D3O+ in H2O—D2O mixtures.
A Comparison of Some Physical Properties of Hydrogen and Deuterium Iodides
Authors: Bates John R. , Halford J. O. , Anderson Leigh C.
Published: November 2004

The absorption spectra and vapor pressures of the hydrogen and deuterium iodides have been measured. The absorption of the hydrogen compound occurs at longer wavelengths than does the deuterium iodide. The vapor pressures are only slightly different, the deuterium iodide having a greater value at a given temperature. The theoretical reasons for these differences are discussed, and equations for the vapor pressures are given as determined by this and other work.
The Crystal Structure of Lepidocrocite
Authors: Ewing F. J.
Published: November 2004

The unit of structure, space group symmetry and detailed atomic arrangement of lepidocrocite are determined from x-ray data, and the existence and location of hydrogen bonds in the structure are established from considerations of interatomic distances. The orthorhombic lattice is end centered on (100), and has the axes a0 = 3.87A, b0 12.51A, and c0 = 3.06A. The space group is Vh17—Amam. The parameters are determined as uFe = —0.332, uO = +0.282, and uOH = +0.075. The structure is described as consisting of iron-centered oxygen octahedra joined by the sharing of edges into two-dimensionally infinite layers, with the successive layers held together by hydrogen bonds. The relationship between the diaspore-goethite structure and the böhmite-lepidocrocite structure is discussed from the standpoint of the coordination theory, and found to depend on two alternative ways of satisfying the electrostatic valence rule.
The Ionization Potential of Acetone Vapor
Authors: Noyes W. Albert
Published: November 2004

The ionization potential of acetone vapor has been measured with a two-electrode tube. The value found agrees within experimental error with that predicted from spectroscopic data.
The Near Infrared Spectrum of Benzene-d6
Authors: Barnes R. Bowling , Brattain R. Robert
Published: November 2004

The transmission spectrum of C6D6 has been studied from 1μ to 13.25μ and the shifts of three of the four infrared active vibrations determined. The results obtained are in substantial agreement with the assumption of a plane symmetrical molecule as outlined by Wilson.

Measurements on C6H6 and thiophene extending from 1μ to 15μ are also presented.
The Theory of Galvanic Potentials. I
Authors: Gross Ph. , Halpern O.
Published: November 2004

In this paper a thermodynamic study of the theory of galvanic electrode potentials is presented. It is shown that, starting from strictly equilibrium conditions, the series of normal electrode potentials can be expressed through other partly known thermodynamic quantities, one group of which refers to the solid phase only, independent of the solvent used, while the other is characterized by the type of solvent.
Entropy and the Absolute Rate of Chemical Reactions. II. Unimolecular Reactions
Authors: Rice O. K. , Gershinowitz Harold
Published: November 2004

In this paper the considerations of the previous paper have been developed further and compared with the theory of reaction rates as formulated in terms of a specifically defined activated complex by Eyring. The theory has been applied to a discussion of various unimolecular reactions. A number of cases have been treated by considering the reverse bimolecular or trimolecular association and discussing the extent to which rotational degrees of freedom must be frozen out in order for the associations to occur. Other cases have been treated by the activated complex method, which involves discussion of the number of free rotations and the frequency of the vibrations in the complex. It has been shown that it is possible to account for the rates of a considerable number of unimolecular reactions by making reasonable assumptions and that there is a considerable class of unimolecular reactions which conform to what is designated as the ``hypothesis of exact orientation,'' the only necessary assumption being that the rotational degrees of freedom of the fragments which recombine in the reverse reaction must be frozen out just sufficiently so that they correspond as regards their entropy terms to the resulting vibrational degrees of freedom of the molecule formed.
The Absolute Rate of Reactions in Condensed Phases
Authors: Wynne-Jones W. F. K. , Eyring Henry
Published: November 2004

The theory of absolute reaction rates is developed for condensed phases. The equation for the rate of a reaction of any order in any phase where the slow process is the passage over an energy barrier consists of the product of a transmission coefficient κ, a frequency kT/h, an equilibrium constant between an activated complex and the reactants and an activity coefficient factor. Previous theories of reaction rates such as Brönsted's, the collision theory of Mc C. Lewis, etc., are seen to be special cases of the general theory. A variety of examples are considered.
Electronic Structures of Polyatomic Molecules. VII. Ammonia and Water Type Molecules and Their Derivatives
Authors: Mulliken Robert S.
Published: November 2004

Spectroscopic and ionization potential data are used in obtaining electron configurations in terms of molecular orbitals for NH3, PH3, H2O, H2S and their derivatives, e.g., CH3NH2, (CH3)2NH, N2H4, H2O2, CH3OH, NH2Cl, ClOH, Cl2O. These electron configurations hold for molecules in their normal states, but can be used in predicting the energy of ``vertically'' excited states, i.e., energies corresponding to nuclear dimensions the same as for the normal state. Frequent close similarities between the spectra of parent molecules and their derivatives are explained (also the similarities between alkyl halides such as CH3I, C2H5I, etc.). Estimates of vertical ionization potentials for the various orbitals used are given. Various points (types of orbitals used, Rydberg series, predissociation) are touched on. The longest wavelength ultraviolet spectra and minimum ionization potential are attributed in the NH3 derivatives to excitation of a nearly nonbonding electron of the N atom, in the H2O and H2S derivatives to excitation of a nonbonding O or S atom electron. (Exception: compounds containing I, Br, and perhaps Cl, where the halogen atom supplies the most easily excited and ionized electron.)
A Comparison of Some Physical Properties of Hydrogen and Deuterium Bromides
Authors: Bates John R. , Halford J. O. , Anderson Leigh C.
Published: November 2004

The absorption spectra and vapor pressures of the hydrogen and deuterium bromides have been measured. The frequency difference between the absorption curves of these compounds is about three times as great as can be accounted for by the zero-point energy differences. Theoretical reasons for this effect are discussed. The vapor pressures are almost identical. The application of Trouton's rule to isotopic compounds is discussed and calculated values for the constant are presented.
The Ultraviolet Absorption Spectra of Cis- and Transdichloroethylenes
Authors: Mahncke H. E. , Noyes W. Albert
Published: November 2004

The absorption spectra of cis- and of transdichloroethylene have been photographed from the visible to 750A. There are continua in the quartz region and at short wavelengths, but discrete bands in the general region of 1300 to 1700A. Two Rydberg series have been found in the cis-form predicting ionization potentials of 9.58 and 9.63 volts. A value in agreement with these figures is found by electron bombardment. No Rydberg series were found in the trans-form, although indications of an ionization potential at about 11.3 volts were obtained by electron bombardment. In both forms the main progressions involve a C=C frequency of about 1400 cm—1, although many prominent differences involving the lowest deformation frequency have been found. A discussion of the various absorption regions has been given, although definite proof of many points must come from other sources.
The Normal State of the Helium Molecule Ion, He2+
Authors: Weinbaum Sidney
Published: November 2004

A variation function constructed of hydrogen-like 1s functions with different values of the effective nuclear charges for He: and He.+ is used in the treatment of the normal state of the helium molecule-ion. The treatment leads to the values De=2.22 e.v. and re=1.097A for the dissociation energy and the internuclear distance, in good agreement with the experimental values.
Direct transition to electroconvection in a homeotropic nematic liquid crystal
Authors: Buka Á. , Dressel B. , Kramer L. , Pesch W.
Published: November 2004

We present an experimental and theoretical investigation of a variant of electroconvection using an unusual nematic liquid crystal in an isotropic configuration (homeotropic alignment). The significance of the system is a direct transition to the convecting state due to the negative conductivity anisotropy and positive dielectric anisotropy. We observe at onset rolls or squares depending on the frequency and amplitude of the applied ac voltage with a strong signature of the zigzag instability. Good agreement with calculations based on the underlying hydrodynamic theory is found. We also construct an extended Swift–Hohenberg model which allows us to capture complex patterns like squares with a quasiperiodic modulation.
On thermal convection in slowly rotating systems
Authors: Busse F. H.
Published: November 2004

The dynamical properties of convection patterns in a fluid layer heated from below and rotating slowly about a horizontal axis are reviewed. Applications to the equatorial regions of planetary and stellar atmospheres are emphasized. Attention is drawn to the wavelike drift of hexagonal convection cells in the azimuthal direction and to the mean flow generated by all convection patterns except for rolls aligned with the axis of rotation.
Measurements of current sheet canting in a pulsed electromagnetic accelerator
Authors: Markusic T. E. , Choueiri E. Y. , Berkery J. W.
Published: November 2004

The phenomenon of current sheet canting in pulsed electromagnetic accelerators is the departure of the plasma sheet (that carries the current) from a plane that is perpendicular to the electrodes to one that is skewed or tipped. Developing an understanding of current sheet canting is important because it can detract from the propellant sweeping capabilities of current sheets and, hence, negatively impact the overall efficiency. In the present study, photographic, magnetic, and laser-interferometric diagnostics were implemented to study current sheets in an experimental pulsed electromagnetic accelerator, using a variety of propellants and pressure levels. The interferometric measurements were used to quantify the canting angle during the stable phase of propagation. The canting angle was found to increase with the atomic mass of the propellant and the current sheet was always found to tilt such that the anode current attachment leads the cathode attachment.
Trapped electron stabilization of ballooning modes in low aspect ratio toroidal plasmas
Authors: Cheng C. Z. , Gorelenkov N. N.
Published: November 2004

The kinetic effects of trapped electron dynamics and finite gyroradii and magnetic drift motion of ions are shown to give rise to a large parallel electric field and hence a parallel current that greatly enhances the stabilizing effect of field line tension for ballooning modes in low aspect ratio toroidal plasmas. For large aspect ratio the stabilizing effect increases (reduces) the β(=2P/B2) threshold for the first (second) stability of the kinetic ballooning mode (KBM) from the magnetohydrodynamics (MHD) β threshold value by a factor proportional to the trapped electron density fraction. For small aspect ratio the stabilizing effect can greatly increase the β threshold of the first stability of KBMs from the MHD β threshold by Sc≃1+(ne/neu)δ, where ne/neu is the ratio of the total electron density to the untrapped electron density, and δ depends on the trapped electron dynamics and finite gyroradii and magnetic drift motion of ions. If ne/neu≫1 as in the National Spherical Torus Experiment (NSTX) [M. Ono, Nucl. Fusion 40, 557 (2000)] with an aspect ratio of ≃1.4, the KBM should be stable for β⩽1 for finite magnetic shear. Therefore, unstable KBMs are expected only in the weak shear region near the radial location of the minimum of the safety factor in NSTX reverse shear discharges.
Viscous fingering as a paradigm of interfacial pattern formation: Recent results and new challenges
Authors: Casademunt Jaume
Published: November 2004

We review recent results on dynamical aspects of viscous fingering. The Saffman–Taylor instability is studied beyond linear stability analysis by means of a weakly nonlinear analysis and the exact determination of the subcritical branch. A series of contributions pursuing the idea of a dynamical solvability scenario associated to surface tension in analogy with the traditional selection theory is put in perspective and discussed in the light of the asymptotic theory of Tanveer and co-workers. The inherently dynamical singular effects of surface tension are clarified. The dynamical role of viscosity contrast is explored numerically. We find that the basin of attraction of the Saffman–Taylor finger depends on viscosity contrast, and that the sensitivity to this parameter is maximal in the usual limit of high viscosity contrast. The competing attractors are identified as closed bubble solutions. We briefly report on recent results and work in progress concerning rotating Hele-Shaw flows, topological singularities and wetting effects, and also discuss future directions in the context of viscous fingering.
Stability of giant vortices in quantum liquids
Authors: Josserand Christophe
Published: November 2004

We show how giant vortices can be stabilized for strong external potentials in Bose–Einstein condensates. We illustrate the formation of these vortices thanks to the Ginzburg–Landau dissipative dynamics for two typical potentials in two spatial dimensions. The giant vortex stability is studied for the particular case of a rotating cylindrical hard wall. Due to axial symmetry the minimization of the perturbed energy is simplified into a one dimensional relaxation dynamics. Solving this 1D minimization problem, we observe that giant vortices are either never stable, or only stable in a finite frequency range. Finally we obtain the marginal curve for the minimum frequency needed to observe a giant vortex.
Homological mirror symmetry, deformation quantization and noncommutative geometry
Authors: Bressler Paul , Soibelman Yan
Published: November 2004

We discuss the possible relationship of homological mirror symmetry with deformation quantization. We speculate that after certain nonlinear “twist” the Fukaya category becomes equivalent to the category of holonomic modules over a quantized algebra of functions.
Braided cyclic cocycles and nonassociative geometry
Authors: Akrami S. E. , Majid S.
Published: November 2004

We use monoidal category methods to study the noncommutative geometry of nonassociative algebras obtained by a Drinfeld-type cochain twist. These are the so-called quasialgebras and include the octonions as braided-commutative but nonassociative coordinate rings, as well as quasialgebra versions Cq(G) of the standard q-deformation quantum groups. We introduce the notion of ribbon algebras in the category, which are algebras equipped with a suitable generalized automorphism σ, and obtain the required generalization of cyclic cohomology. We show that this braided cyclic cohomology is invariant under a cochain twist. We also extend to our generalization the relation between cyclic cohomology and differential calculus on the ribbon quasialgebra. The paper includes differential calculus and cyclic cocycles on the octonions as a finite nonassociative geometry, as well as the algebraic noncommutative torus as an associative example.
On the contribution of local current density to neoclassical tearing mode stabilization
Authors: Sauter O.
Published: November 2004

Neoclassical tearing modes are driven by the reduction of bootstrap current inside the island due to the flattening of the pressure profile. This current perturbation enhances the magnetic perturbation responsible for the island formation. Therefore it is well known that local current drive (CD) can be used to compensate this perturbation and stabilize the mode. Several forms of the current drive contribution to the modified Rutherford equation have been proposed. Analytical fits of these contributions are provided in order to facilitate their comparison with experiments and another contribution is proposed. Since the bounce and transit frequencies are much larger than the collision frequency and the modulation frequency of the CD source in phase with the island, it is argued that the effective current driven density profile is a flux function. Assuming an exponential profile leads to no difference between modulated and continuous application of current drive. The various forms differ mainly at small island width and the possibility to differentiate amongst them experimentally is discussed.
Deformation quantization in singular spaces
Authors: Maldonado-Mercado Cesar
Published: November 2004

We present a method of quantizing analytic spaces X immersed in an arbitrary smooth ambient manifold M. Remarkably our approach can be applied to singular spaces. We begin by quantizing the cotangent bundle of the manifold M. Using a supermanifold framework we modify the Fedosov construction in a way such that the ⋆-product of the functions lifted from the base manifold turns out to be the usual commutative product of smooth functions on M. This condition allows us to lift the ideals associated to the analytic spaces on the base manifold to form left (or right) ideals on (OΩ1M[[ℏ]],⋆ℏ) in a way independent of the choice of generators and leading to a finite set of PDEs defining the functions in the quantum algebra associated with X. Some examples are included.
A combinatorial approach to the set-theoretic solutions of the Yang–Baxter equation
Authors: Gateva-Ivanova Tatiana
Published: November 2004

A bijective map r: X2→X2, where X={x1,…,xn} is a finite set, is called a set-theoretic solution of the Yang–Baxter equation (YBE) if the braid relation r12r23r12=r23r12r23 holds in X3. A nondegenerate involutive solution (X,r) satisfying r(xx)=xx, for all x∈X, is called square-free solution. There exist close relations between the square-free set-theoretic solutions of YBE, the semigroups of I-type, the semigroups of skew polynomial type, and the Bieberbach groups, as it was first shown in a joint paper with Michel Van den Bergh. In this paper we continue the study of square-free solutions (X,r) and the associated Yang–Baxter algebraic structures—the semigroup S(X,r), the group G(X,r) and the k-algebra A(k,X,r) over a field k, generated by X and with quadratic defining relations naturally arising and uniquely determined by r. We study the properties of the associated Yang–Baxter structures, and prove a conjecture of the present author that the three notions: a square-free solution of (set-theoretic) YBE, a semigroup of I type, and a semigroup of skew-polynomial-type, are equivalent. This implies that the Yang–Baxter algebra A(k,X,r) is a Poincaré–Birkhoff–Witt-type algebra, with respect to some appropriate ordering of X. We conjecture that every square-free solution of YBE is retractable, in the sense of Etingof–Schedler–Solovyev.
Mirror symmetry and noncommutative geometry of A∞-categories
Authors: Soibelman Yan
Published: November 2004

Homological mirror symmetry aims to explain the phenomenon of mirror symmetry in the language of A∞-categories and their deformation theory. In these notes I discuss various aspects of this approach from the point of view of noncommutative algebraic geometry in the tensor category of graded vector spaces.
On a dual inductively coupled plasma for direct and remote plasma in a reactor
Authors: Uhm Saehoon , Lee Kyong-Ho , Chang Hong Young , Chung Chin Wook
Published: November 2004

A dual inductively coupled plasma (ICP) system in which a remote ICP (upper ICP) with small volume is attached to a main ICP (lower ICP) is developed. Two ICP antennas are connected in parallel and a variable capacitor Cvar is installed in series at the end of the main ICP antenna. By adjusting the capacitance of the variable capacitor, the plasma densities and the electron temperatures in the remote region and the main region are controlled. The electron energy distribution functions (EEDFs) and plasma potential from the EEDFs are measured along z axis. It is found that there is a potential dip in the midway of two ICP antennas and the potential dip is formed to keep two plasmas quasineutral. In two regions, the EEDFs in high energy range are almost same (nonlocal) but they are different in low energy range because low energy electrons cannot overcome the potential dip.
Response to “Comment on ‘Kinetic effects on the parametric decays of circularly polarized electromagnetic waves in a relativistic pair plasma’” [Phys. Plasmas 11, 4882 (2004)]
Authors: Muñoz Víctor
Published: November 2004

The issues raised by Stenflo and Shukla in their Comment are addressed in this Response.
Fluctuations in turbulent Rayleigh–Bénard convection: The role of plumes
Authors: Grossmann Siegfried , Lohse Detlef
Published: November 2004

Our unifying theory of turbulent thermal convection [Grossmann and Lohse, J. Fluid. Mech. 407, 27 (2000); Phys. Rev. Lett. 86, 3316 (2001); Phys. Rev. E 66, 016305 (2002)] is revisited, considering the role of thermal plumes for the thermal dissipation rate and addressing the local distribution of the thermal dissipation rate, which had numerically been calculated by Verzicco and Camussi [J. Fluid Mech. 477, 19 (2003); Eur. Phys. J. B 35, 133 (2003)]. Predictions for the local heat flux and for the temperature and velocity fluctuations as functions of the Rayleigh and Prandtl numbers are offered. We conclude with a list of suggestions for measurements that seem suitable to verify or falsify our present understanding of heat transport and fluctuations in turbulent thermal convection.
Coherent solutions for relativistic vectorial fields
Authors: Maccari Attilio
Published: November 2004

Approximate interacting localized solutions of a vectorial massive nonlinear equation are obtained by using the asymptotic perturbation (AP) method, based on Fourier expansion and spatio-temporal rescaling. The amplitude slow modulation of Fourier modes is described by a system of nonlinear evolution equations solvable via an appropriate change of variables. Various types of localized solutions (dromions, lumps, ring solitons, and breathers) as well as multiple soliton and instanton solutions can be explicitly constructed and their interaction is completely elastic, because they pass through each other and preserve their shape, the only change being a phase shift.
Reforming of ethanol in a microwave surface-wave plasma discharge
Authors: Yanguas-Gil A. , Hueso J. L. , Cotrino J. , Caballero A. , González-Elipe A. R.
Published: November 2004

Hydrogen production through plasma reforming of ethanol at room temperature and moderate pressure has been carried out in a microwave surface-wave reactor. Both pure ethanol and mixtures ethanol-water have been studied. The reforming yield was almost 100% in all conditions with H2, solid carbon, CO and CO2 as the main reaction products. In the mixture ethanol-water the formation of solid C was avoided. The optical emission spectroscopy analysis has shown that the formation of the excited species CO*, CH* and C2* depends on the plasma mixture. The temperature of the OH* species was determined by analyzing the shape profile of its emission band.
Flux pinning behavior of incomplete multilayered lattice structures in YBa2Cu3O7−d
Authors: Barnes Paul N. , Haugan Timothy J. , Varanasi Chakrapani V. , Campbell Timothy A.
Published: November 2004

Magnetization results of YBa2Cu3O7−d films processed with interlayers of CeO2 inclusions are presented. Unexpected flux pinning results that are different from previous observations with nanoparticulate layered inclusions were observed. Flux pinning was found to be in some cases either slightly improved at either low fields <0.5T or in other cases at high fields >8T although degraded, sometimes severely, at interim magnetic fields. Most unexpectedly, the pinning performance of the various samples rapidly converges as the temperature is reduced from 77 to 65K, causing all films to have similar Jc(H) behavior at 65K even though dramatically different at 77K.
Capillary kinetics of thin polymer films in permeable microcavities
Authors: Suh Kahp Y. , Kim Pilnam , Lee Hong H.
Published: November 2004

We present a Poiseuille model that can explain the rate of capillary rise of thin polymer films in permeable microcavities. In comparison to the traditional Poiseuille formulation, two features of the system were considered: the permeable nature of the enclosure and the effect of thin polymer films that are confined to the substrate. The model predicts that the rate is inversely proportional to the channel width, contrary to what the original Poiseuille model predicts, and it is proportional to the initial film thickness, which the original model cannot account for. The modified model is in satisfactory agreement with experimental data.
Effects of the ratio of hardness to Young’s modulus on the friction and wear behavior of bilayer coatings
Authors: Ni Wangyang , Cheng Yang-Tse , Lukitsch Michael J. , Weiner Anita M. , Lev Lenoid C. , Grummon David S.
Published: November 2004

We present a study of the effects of the ratio of hardness to Young’s modulus on the friction and wear behavior of layered composite coatings. Layered coating structures with the same surface coating but different interlayers were prepared by physical vapor deposition. We found that the ratio of hardness to Young’s modulus plays an important role in determining the friction coefficient and wear resistance of layered composite coatings. A low friction coefficient and high wear resistance can be achieved in structures with high ratio of hardness to Young’s modulus and moderately high hardness.
Metal-semiconductor transition in armchair carbon nanotubes by symmetry breaking
Authors: Li Yan , Rotkin Slava V. , Ravaioli Umberto
Published: November 2004

The electronic band structure of armchair carbon nanotubes may be considerably modified by potentials with angular dependence. Different angular modes Vq∼cosqθ have been studied within a tight-binding scheme. Using symmetry arguments, we demonstrate a bandgap opening in these metallic nanotubes when certain selection rules are satisfied for both potential and nanotube structure. We estimate the bandgap opening as a function of both the external potential strength and the nanotube radius and suggest an effective mechanism of metal-semiconductor transition by combination of different forms of perturbations.
Analysis of the intermolecular interaction of nanocomposites by THz spectroscopy
Authors: Nagai Naoto , Imai Tomoko , Fukasawa Ryoichi , Kato Koya , Yamauchi Koji
Published: November 2004

Transmission and reflection measurements on polyamide nanocomposite films were performed in the THz frequency region, and the dielectric function was calculated using the Debye model to interpret the data. The relaxation time from the signal of orientation polarization due to the permanent dipole moments exhibits intermolecular interaction. In nanocomposites, the extreme increase of the interaction from polymer clay was first observed by THz spectroscopy. The essential interaction was thought to occur between the amide functional (−NH) group in polyamide-6 and the surface of the clay by considering the correlation with the results of infrared spectroscopy.
Strain-relieved, dislocation-free InxGa1−xAs∕GaAs(001) heterostructure by nanoscale-patterned growth
Authors: Lee S. C. , Dawson L. R. , Pattada B. , Brueck S. R. J. , Jiang Y.-B. , Xu H. F.
Published: November 2004

A strain-relieved, dislocation-free InxGa1−xAs layer is selectively grown on nanoscale SiO2-patterned GaAs(001) by molecular beam epitaxy. By localizing the epitaxial area to a periodic array of nanoscale circular holes opened in a SiO2 mask and allowing the InxGa1−xAs epilayers selectively grown on adjacent holes to coalesce over the SiO2 mask by lateral overgrowth, the strain of the resulting InxGa1−xAs layer (x=0.06) is relieved with a dramatically decreased generation of misfit dislocations. These experimental results qualitatively support the basic idea of the Luryi-Suhir proposal [Appl. Phys. Lett. 49, 140 (1986)].
Experimental demonstration of nonreciprocal amplified spontaneous emission in a CoFe clad semiconductor optical amplifier for use as an integrated optical isolator
Authors: Vanwolleghem Mathias , Van Parys Wouter , Van Thourhout Dries , Baets Roel , Lelarge François , Gauthier-Lafaye Olivier , Thedrez Bruno , Wirix-Speetjens Roel , Lagae Liesbet
Published: November 2004

Experimental results are presented for an integrated-optical-waveguide-isolator concept. This concept is based on inducing the transverse magneto-optic Kerr effect in a semiconductor InP-based optical amplifier (SOA) by using a transversely magnetized ferromagnetic metal as an electrical contact. As a result, the SOA exhibits nonreciprocal loss/gain for TM polarized light and is easily monolithically integrated with other InP-based active photonic devices. We have designed, fabricated and characterized prototype ferromagnetic metal-clad optical amplifiers for an operation wavelength of 1300nm. In these first generation devices we obtained isolation strengths of up to 2.0dB∕mm.
Manipulation of nanowires in suspension by ac electric fields
Authors: Fan D. L. , Zhu F. Q. , Cammarata R. C. , Chien C. L.
Published: November 2004

Nanowires are potential building blocks for nanoscale devices. Manipulation of nanowires in suspension has been a formidable problem. Using ac electric fields applied to strategically designed microelectrodes, nanowires in suspension can be driven to align, to chain, to accelerate in directions parallel and perpendicular to its orientation, to concentrate onto designated places, and to disperse in a controlled manner with high efficiency despite an extremely low Reynolds number at the level of 10−5. The manipulation of nanowires can also be applied to other small elongated entities such as carbon nanotubes.
Dopant profiling in vertical ultrathin channels of double-gate metal–oxide–semiconductor field-effect transistors by using scanning nonlinear dielectric microscopy
Authors: Masahara Meishoku , Hosokawa Shinichi , Matsukawa Takashi , Endo Kazuhiko , Naitou Yuuichi , Tanoue Hisao , Suzuki Eiichi
Published: November 2004

Nanometer-scale dopant profiling in the vertical ultrathin channels (UTCs) of double-gate metal–oxide–semiconductor field-effect transistors has been performed by using scanning nonlinear dielectric microscopy. UTCs 18–58nm thick and 175nm high were formed on a bulk silicon substrate by orientation-dependent wet etching. An n+∕p junction was fabricated on the top of the UTC by angled ion implantation. By beveling the UTC with an ultragentle angle, the vertical size of the UTC was amplified by a factor of 86. Using the beveled samples, the channel thickness dependence of the dopant depth profile in the UTC was quantitatively investigated. It was found that a significant dopant loss occurs when the channel thickness is reduced to 18nm.
Precession-dominated switching of synthetic antiferromagnets
Authors: Kim Joo-Von , Devolder T. , Chappert C. , Maufront C. , Fournel R.
Published: November 2004

We present theoretical results of precession-dominated switching of synthetic antiferromagnet elements. A fast (subnanosecond) reversal mode is shown to be possible for perfectly compensated structures (zero net moment) with pulsed magnetic fields, where the antiparallel alignment is largely preserved during reversal. By using component ferromagnets with different magnetocrystalline and shape anisotropies, we show that it is possible to select the final magnetic state of the synthetic antiferromagnet with pulsed fields alone. Applications to magnetic memory devices are discussed.
Bistable superconducting quantum interference device with built-in switchable π∕2 phase shift
Authors: Smilde Henk-Jan H. , Ariando  , Rogalla Horst , Hilgenkamp Hans
Published: November 2004

Superconducting quantum interference devices (SQUIDs) have been realized with a built-in π∕2 phase shift of the superconducting wave function. Its design is inspired by the phase-shifter concept, first proposed by Ioffe et al. [Nature 398, 679 (1999)] as the key element in a solid-state qubit configuration. It exploits the dx2−y2 order parameter symmetry in the high-Tc cuprates in multilayer structures based on YBa2Cu3O7-Nb ramp-type Josephson contacts. By reversing the sign of the persistent circulating current in the phase-shifting element, the π∕2 SQUID can be controllably switched between two energetically degenerate ground states, with complementary magnetic flux dependencies.
Alternative surface passivation on germanium for metal-oxide-semiconductor applications with high-k gate dielectric
Authors: Wu Nan , Zhang Qingchun , Zhu Chunxiang , Chan D. S. H. , Li M. F. , Balasubramanian N. , Chin Albert , Kwong Dim-Lee
Published: November 2004

An alternative surface passivation process for high-k Ge metal-oxide-semiconductor (MOS) device has been studied. The surface SiH4 annealing was implemented prior to HfO2 deposition. X-ray photoelectron spectroscopy analysis results show that the SiH4 surface passivation can greatly prevent the formation of unstable germanium oxide at the surface and suppress the Ge out-diffusion after the HfO2 deposition. The electrical measurement shows that an equivalent oxide thickness of 13.5Å and a leakage current of 1.16×10−5A∕cm2 at 1V gate bias was achieved for TaN∕HfO2∕Ge MOS capacitors with the SiH4 surface treatment.
(
Bi
,
La
)
4
Ti
3
O
12
(BLT) thin films grown from nanocrystalline perovskite nuclei for ferroelectric memory devices
Authors: Kim N. K. , Yeom S. J. , Kweon S. Y. , Choi E. S. , Sun H. J. , Roh J. S. , Sohn H. C. , Lee D. W. , Kim H. S. , Choi B. H. , Kim J. W. , Choi K. J. , Seong N. J. , Yoon S. G.
Published: November 2004

Using nanocrystalline perovskite nuclei, (117) oriented-(Bi,La)4Ti3O12(BLT) thin films were grown using a noble bake process for nonvolatile ferroelectric memory devices. The c-axis oriented BLT thin films have a remanent polarization (2Pr) of 8.0μC∕cm2 at a 3V driving voltage, and the (117) oriented films have a 2Pr value of about 25μC∕cm2. The BLT capacitors, grown on a platinum electrode via nanocrystalline perovskite nuclei, had fatigue and imprint free characteristics after applying 1×1011 switching cycles and for ten years at a 125°C stress. The average sensing margin of the (117) oriented BLT thin films was approximately 700mV for a 0.65μm2 cell size and a sufficient signal margin for ten years was indicated, based on the extrapolation of the measured data for high density ferreoelectric random access memory applications.
Properties of highly Cr-doped AlN
Authors: Polyakov A. Y. , Smirnov N. B. , Govorkov A. V. , Frazier R. M. , Liefer J. Y. , Thaler G. T. , Abernathy C. R. , Pearton S. J. , Zavada J. M.
Published: November 2004

Cr concentrations of ∼2at.% were incorporated into AlN during growth by molecular beam epitaxy. Under optimized conditions, single-phase, insulating AlCrN is produced whose band gap shows a small (0.1–0.2eV) decrease from the value for undoped AlN (6.2eV), a decrease in a-plane lattice constant and the introduction of two absorption bands at 3 and 5eV into the band gap. This material shows ferromagnetism with a Curie temperature above 300K as judged from the difference in field-cooled and zero-field-cooled magnetization. For nonoptimized growth, second phases of Cr2N and AlxCry are produced in the AlN and the material is conducting (∼1000Ωcm) with activation energy for conduction of 0.19eV and apparent band gap of 5.8eV.
Atomic-scale structural analyses of epitaxial Co∕Re superlattices
Authors: Xu Wentao , De Long Lance E. , Charlton Timothy , Chisholm Matthew , Lederman David
Published: November 2004

High-resolution transmission electron microscopy and scanning transmission electron microscopy (STEM) have been used to investigate atomic-scale structural properties of Co∕Re trilayers and superlattices grown via magnetron sputtering. The sample growth was epitaxial with the (101¯0) plane of Co and Re parallel to the (112¯0) plane of Al2O3, and the [001] direction of Re and Co coinciding with that of the Al2O3. Both low-angle and high-angle Z-contrast STEM images show a very uniform layer thickness. However, the interface roughness between the Re and Co layers monotonically increases with interface distance from the substrate. These results strongly imply that, in the epitaxial Re∕Co superlattice system, interface roughness plays a more important role in the giant magnetoresistance effect than thickness fluctuations of the spacer layer. Previous anisotropic magnetoresistance measurements can be explained in terms of the observed atomic-scale structure.
Charge carrier transport in an emissive layer of green electrophosphorescent devices
Authors: Matsusue Noriyuki , Ikame Satoshi , Suzuki Yuichiro , Naito Hiroyoshi
Published: November 2004

Charge carrier generation and transport in fac tris (2-phenylpyridine) iridium (III) (Ir(ppy)3) doped in 4,4′-N,N′-dicarbazole-biphenel (CBP) thin films have been studied in terms of time-of-flight and time-resolved photoluminescence spectroscopies. It is found that the excitation energy rapidly transfer from CBP to Ir(ppy)3, and that the charge carriers are generated on Ir(ppy)3 sites. With increasing Ir(ppy)3 concentration, the electron drift mobility is slightly decreased, while the hole transit signals become unobservable. The electron and hole transport properties of Ir(ppy)3 doped CBP thin films result from the energy levels of the lowest unoccupied molecular orbital and the highest occupied molecular orbital of Ir(ppy)3 with respect to those of CBP.
Single-molecule fluorescence microscopy and Raman spectroscopy studies of RNA bound carbon nanotubes
Authors: Rao Rahul , Lee Janet , Lu Qi , Keskar Gayatri , Freedman Katherine O. , Floyd William C. , Rao Apparao M. , Ke Pu Chun
Published: November 2004

While present studies on the integration of single-walled carbon nanotubes (SWNTs) with biomolecules have centered primarily on deoxyribonucleic acid and proteins, this report is focused on the binding of SWNTs with ribonucleic acid polymer poly(rU). We present fluorescence and spectroscopic evidences for the binding of poly(rU) molecules along the contour of isolated SWNTs which suggests that the π-stacking may dominate the hydrophobic interaction between the poly(rU) bases and the π-electrons of the SWNTs.