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Showing papers on "Quadrupole published in 2006"


Journal ArticleDOI
29 Jun 2006-Langmuir
TL;DR: The UV-visible spectra of the aqueous colloids show distinct bands corresponding to dipole and quadrupole plasmon modes, for diameters above 100 nm, in close agreement with predictions based on Mie theory.
Abstract: A modified seeded growth process has been used for the controlled synthesis of quasispherical, CTAB-stabilized gold nanoparticles from 12 up to 180 nm with narrow size distributions The UV-visible spectra of the aqueous colloids show distinct bands corresponding to dipole and quadrupole plasmon modes, for diameters above 100 nm, in close agreement with predictions based on Mie theory The assignment of the modes is demonstrated by calculation of near field enhancement maps based on the boundary element method Apart from other applications, since absorption is drastically reduced above 600 nm, while scattering is largely increased, these particles open new possibilities for construction of highly efficient photonic structures

351 citations


Journal ArticleDOI
TL;DR: In this paper, the authors apply the multipole vector framework to full-sky maps derived from the first-year Wilkinson Microwave Anisotropy Probe (WMAP) data.
Abstract: We apply the multipole vector framework to full-sky maps derived from the first-year Wilkinson Microwave Anisotropy Probe (WMAP) data. We significantly extend our earlier work showing that the two lowest cosmologically interesting multipoles, � = 2 and 3, are not statistically isotropic. These results are compared to the findings obtained using related methods. In particular, we show that the planes of the quadrupole and the octopole are unexpectedly aligned. Moreover, the combined quadrupole plus octopole is surprisingly aligned with the geometry and direction of motion of the Solar system: the plane they define is perpendicular to the ecliptic plane and to the plane defined by the dipole direction, and the ecliptic plane carefully separates stronger from weaker extrema, running within a couple of degrees of the null-contour between a maximum and a minimum over more than 120 ◦ of the sky. Even given the alignment of the quadrupole and octopole with each other, we find that their alignment with the ecliptic is unlikely at >98 per cent confidence level (CL), and argue that it is in fact unlikely at >99.9 per cent CL. Most of the � = 2 and 3 multipole vectors of the known Galactic foregrounds are located far from those of the observed sky, strongly suggesting that residual contamination by such foregrounds is unlikely to be the cause of the observed correlations. Multipole vectors,

295 citations


Journal ArticleDOI
TL;DR: It is shown that by allowing the large-scale spatial geometry of the authors' universe to be plane symmetric with eccentricity at decoupling or order 10(-2), the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.
Abstract: The recent 3 yr Wilkinson Microwave Anisotropy Probe data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit Lambda-cold dark matter prediction. We show that by allowing the large-scale spatial geometry of our universe to be plane symmetric with eccentricity at decoupling or order 10(-2), the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.

206 citations


Journal ArticleDOI
TL;DR: The experimental observation of scalar multipole solitons in highly nonlocal nonlinear media, including dipole, tripole, quadrupole, and necklace-typesolitons, organized as arrays of out-of-phase bright spots is presented.
Abstract: We present the experimental observation of scalar multipole solitons in highly nonlocal nonlinear media, including dipole, tripole, quadrupole, and necklace-type solitons, organized as arrays of out-of-phase bright spots. These complex solitons are metastable, but with a large parameters range where the instability is weak, permitting their experimental observation.

200 citations


Journal ArticleDOI
TL;DR: In this paper, the large-scale spatial geometry of our universe was shown to be plane-symmetric with eccentricity at decoupling or order 10^{-2, and the quadrupole amplitude can be reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.
Abstract: The recent three-year WMAP data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit \Lambda CDM prediction. We show that, allowing the large-scale spatial geometry of our universe to be plane-symmetric with eccentricity at decoupling or order 10^{-2}, the quadrupole amplitude can be drastically reduced without affecting higher multipoles of the angular power spectrum of the temperature anisotropy.

178 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the gravitational radiation field of point particles with spins within the framework of the multipolar-post-Newtonian wave generation formalism and derived the spin-orbit coupling effects in the binary's mass and current quadrupole moments.
Abstract: Motivated by the search for gravitational waves emitted by binary black holes, we investigate the gravitational radiation field of point particles with spins within the framework of the multipolar-post-Newtonian wave generation formalism. We compute: (i) the spin-orbit (SO) coupling effects in the binary's mass and current quadrupole moments one post-Newtonian (1PN) order beyond the dominant effect, (ii) the SO contributions in the gravitational-wave energy flux and (iii) the secular evolution of the binary's orbital phase up to 2.5PN order. Crucial ingredients for obtaining the 2.5PN contribution in the orbital phase are the binary's energy and the spin precession equations, derived in paper I of this series. These results provide more accurate gravitational-wave templates to be used in the data analysis of rapidly rotating Kerr-type black-hole binaries with the ground-based detectors LIGO, Virgo, GEO 600 and TAMA300, and the space-based detector LISA.

173 citations


Journal ArticleDOI
TL;DR: In this article, a measurement of the quadrupole power spectrum in the 2DF QSO redshift survey was performed using an algorithm parallel to that for estimating the standard monopole power signal without first requiring computation of the correlation function or anisotropic power spectrum.
Abstract: We report on a measurement of the quadrupole power spectrum in the two degree field (2dF) QSO redshift (2QZ) survey. The analysis used an algorithm parallel to that for estimating the standard monopole power spectrum without first requiring computation of the correlation function or the anisotropic power spectrum. The error on the quadrupole spectrum was rather large, but the best-fit value of the bias parameter from the quadrupole spectrum is consistent with that from previous investigations of the 2dF data.

171 citations


Journal ArticleDOI
TL;DR: In this paper, the systematics of ground-state quadrupole correlations of binding energies and mean-square charge radii for all even-even nuclei, from the superheavies up to the super-heavy ones, were discussed.
Abstract: We discuss the systematics of ground-state quadrupole correlations of binding energies and mean-square charge radii for all even-even nuclei, from ${}^{16}$O up to the superheavies, for which data are available. To that aim we calculate their correlated $J=0$ ground state by means of the angular-momentum and particle-number projected generator coordinate method, using the axial mass quadrupole moment as the generator coordinate and self-consistent mean-field states restricted only by axial, parity, and time-reversal symmetries. The calculation is performed within the framework of a nonrelativistic self-consistent mean-field model by use of the same Skyrme interaction SLy4 and to a density-dependent pairing force to generate the mean-field configurations and to mix them. These are the main conclusions of our study: (i) The quadrupole correlation energy varies between a few 100 keV and about 5.5 MeV. It is affected by shell closures, but varies only slightly with mass and asymmetry. (ii) Projection on angular momentum $J=0$ provides the major part of the energy gain of up to about 4 MeV; all nuclei in the study, including doubly magic ones, gain energy by deformation. (iii) The mixing of projected states with different intrinsic axial deformations adds a few 100 keV up to 1.5 MeV to the correlation energy. (iv) Typically nuclei below mass $A\ensuremath{\le}60$ have a larger correlation energy than static deformation energy whereas the heavier deformed nuclei have larger static deformation energy than correlation energy. (v) Inclusion of the quadrupole correlation energy improves the description of mass systematics, particularly around shell closures, and of differential quantities, namely two-nucleon separation energies and two-nucleon gaps. The correlation energy provides an explanation of ``mutually enhanced magicity.'' (vi) The correlation energy tends to decrease the shell effect on binding energies around magic numbers, but the magnitude of the suppression is not large enough to explain the relative overbinding at $N=82$ and $N=126$ neutron-shell closures in mean-field models. (vii) Charge radii are also found to be sensitive to the quadrupole correlations. Static quadrupole deformations lead to a significant improvement of the overall systematics of charge radii. The dynamical correlations improve the local systematics of radii, in particular around shell closures. Although the dynamical correlations might reduce the charge radii for specific nuclei, they lead to an overall increase of radii when included, in particular in light nuclei.

126 citations


Journal ArticleDOI
TL;DR: Ren et al. as discussed by the authors traced the physical origin of the quadrupole magnetic field to a current of electrons that flows along the lines in and out of the inner reconnection region to maintain charge neutrality.
Abstract: A quadrupole pattern of the out-of-plane component of the magnetic field inside a reconnection region is seen as an important signature of the Hall-magnetohydrodynamic regime of reconnection It has been first observed in numerical simulations and just recently confirmed in the Magnetic Reconnection Experiment [Y Ren, M Yamada, S Gerhardt, H Ji, R Kulsrud, and A Kuritsin, Phys Rev Lett 95, 055003 (2005)] and also seen in spacecraft observations of Earth’s magnetosphere In this study, the physical origin of the quadrupole field is analyzed and traced to a current of electrons that flows along the lines in and out of the inner reconnection region to maintain charge neutrality The role of the quadrupole magnetic field in the overall dynamics of the reconnection process is discussed In addition, the bipolar poloidal electric field is estimated and its effect on ion motions is emphasized

114 citations


Journal ArticleDOI
TL;DR: The static and dynamic electric dipole, quadrupole, and octupole polarizabilities of the alkaline-earth atoms (beryllium, magnesium, calcium, strontium, and barium) in the ground state were calculated as discussed by the authors.
Abstract: The static and dynamic electric dipole, quadrupole, and octupole polarizabilities of the alkaline-earth atoms (beryllium, magnesium, calcium, strontium, and barium) in the ground state were calculated. The dynamic polarizabilities obtained were used to calculate the van der Waals coefficients C 6, C 8, and C 10 of alkaline-earth metal dimers for the interaction of two like atoms in the ground state. The results are compared with other theoretical and experimental data.

103 citations


Journal ArticleDOI
TL;DR: In this paper, the physical origin of the quadrupole field is analyzed and traced to a current of electrons that flows along the lines in and out of the inner reconnection region to maintain charge neutrality.
Abstract: A quadrupole pattern of the out-of-plane component of the magnetic field inside a reconnection region is seen as an important signature of the Hall-magnetohydrodynamic (Hall-MHD) regime of reconnection. It has been first observed in numerical simulations and just recently confirmed in the MRX (Magnetic Reconnection Experiment) [M. Yamada, H. Ji, S. Hsu, T. Carter, R. Kulsrud, N. Bertz, F. Jobes, Y. Ono, and F. Perkins, Phys. Plasmas 4, 1936 (1997)] and also seen in spacecraft observations of Earth's magnetosphere. In this study, the physical origin of the quadrupole field is analyzed and traced to a current of electrons that flows along the lines in and out of the inner reconnection region to maintain charge neutrality. The role of the quadrupole magnetic field in the overall dynamics of the reconnection process is discussed. In addition, the bipolar poloidal electric field is estimated and its effect on ion motions is emphasized.

Journal ArticleDOI
TL;DR: This paper presents a general coarse-grained molecular mechanics model based on electric point multipole expansion and Gay-Berne potential, which has been applied to rigid-body molecular dynamics simulations of molecular liquids including benzene and methanol.
Abstract: This paper presents a general coarse-grained molecular mechanics model based on electric point multipole expansion and Gay-Berne [J. Chem. Phys. 74, 3316 (1981)] potential. Coarse graining of van der Waals potential is achieved by treating molecules as soft uniaxial ellipsoids interacting via a generalized anisotropic Gay-Berne function. The charge distribution is represented by point multipole expansion, including point charge, dipole, and quadrupole moments placed at the center of mass. The Gay-Berne and point multipole potentials are combined in the local reference frame defined by the inertial frame of the all-atom counterpart. The coarse-grained model has been applied to rigid-body molecular dynamics simulations of molecular liquids including benzene and methanol. The computational efficiency is improved by several orders of magnitude, while the results are in reasonable agreement with all-atom models and experimental data. We also discuss the implications of using point multipole for polar molecules capable of hydrogen bonding and the applicability of this model to a broad range of molecular systems including highly charged biopolymers.

Journal ArticleDOI
TL;DR: An implementation of the origin-independent optical rotation tensor, which includes electric dipole-magnetic dipole and electric dipoles-electric quadrupole polarizability and a damping constant has been introduced into the linear response equations to treat both resonance and nonresonance regions of optical activity.
Abstract: We outline an implementation of the origin-independent optical rotation tensor, which includes electric dipole-magnetic dipole and electric dipole-electric quadrupole polarizability. The method is based on approximate time-dependent density functional theory. We utilize time-periodic magnetic-field-dependent basis functions as well as a modified velocity-gauge formulation of dynamic polarizability tensors in order to obtain a gauge-origin independence. To ensure gauge-origin independence of the results within a given numerical accuracy, density fit coefficient derivatives are employed. A damping constant has been introduced into the linear response equations to treat both resonance and nonresonance regions of optical activity. We present calculations for trans-2,3-dimethyloxirane and derivatives thereof as well as calculations for androst-4,17-dien-3-one. In the Appendix, we derive the equivalence between the common-gauge origin and gauge-including atomic orbitals formulations for the optical rotation tensor in time-dependent DFT.

Journal ArticleDOI
TL;DR: In this paper, the relativistic configuration-interaction methods were used to calculate the atomic quadrupole moments and hyperfine constants of the metastable {sup 2}D{sub 3/2,5/2} states.
Abstract: Atomic quadrupole moments and hyperfine constants of the metastable {sup 2}D{sub 3/2,5/2} states of Ca{sup +}, Sr{sup +}, Ba{sup +}, Yb{sup +}, and Hg{sup +} are calculated by the multiconfiguration Dirac-Hartree-Fock and relativistic configuration-interaction methods. For Hg{sup +}, the configuration is 5d{sup 9}6s{sup 2}. For the other ions, the configuration consists of a single d-electron outside a set of closed shells. Current interest in the quadrupole moments of these states is due to the fact that optical transitions of these ions may be useful as references for frequency standards. Energy shifts of the metastable states due to the interactions of the quadrupole moments with external electric field gradients are among the largest sources of error in these frequency standards. For the quadrupole moments, agreement is obtained to within about 10% with the available measurements. For the hyperfine constants, good agreement is obtained with measurements and with other calculations, except for the A factors of the {sup 2}D{sub 5/2} states of Sr{sup +}, Ba{sup +}, and Yb{sup +}, where the correlation effects are so large that they reverse the sign of the constant relative to the Dirac-Hartree-Fock value. As a test of the Hg{sup +} calculational methods, quadrupole moments and hyperfinemore » constants are calculated for the 5d{sup 9}6s{sup 2} {sup 2}D{sub 3/2,5/2} states in isoelectronic neutral Au. This yields a value of the nuclear quadrupole moment Q({sup 197}Au)=+0.587(29) b.« less

Journal ArticleDOI
TL;DR: In this article, it was shown that the evolution of the inflationary perturbations is equivalent to the scattering by this potential and a useful dictionary between the scattering data and observables is established.
Abstract: Within the effective field theory of inflation, an initialization of the classical dynamics of the inflaton with approximate equipartition between the kinetic and potential energy of the inflaton leads to a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to an attractive potential in the wave equations for the mode functions of curvature and tensor perturbations. The evolution of the inflationary perturbations is equivalent to the scattering by this potential and a useful dictionary between the scattering data and observables is established. Implementing methods from scattering theory we prove that this attractive potential leads to a suppression of the quadrupole moment for CMB and B-mode angular power spectra. The scale of the potential is determined by the Hubble parameter during slow roll. Within the effective field theory of inflation at the grand unification (GUT) energy scale we find that if inflation lasts a total number of e-folds N{sub tot}{approx}59, there is a 10%-20% suppression of the CMB quadrupole and about 2%-4% suppression of the tensor quadrupole. The suppression of higher multipoles is smaller, falling off as 1/l{sup 2}. The suppression is much smaller for N{sub tot}>59, therefore if the observable suppression originates inmore » the fast roll stage, there is the upper bound N{sub tot}{approx}59.« less

Journal ArticleDOI
TL;DR: In this article, the authors investigated the magnetic field configuration of a rotating star with a non-dipole magnetic field in full three-dimensional (3D) magnetohydrodynamic (MHD) simulations.
Abstract: Disc accretion to a rotating star with a non-dipole magnetic field is investigated for the first time in full three-dimensional (3D) magnetohydrodynamic (MHD) simulations. We investigated the cases of (1) pure dipole, (2) pure quadrupole, and (3) dipole plus quadrupole fields. Simulations have shown that in each case the structure of the funnel streams and associated hot spots on the surface of the star have specific features connected with the magnetic field configuration. In the case (1), matter accretes in two funnel streams which form two arch-like spots near the magnetic poles. In the case (3), most of the matter flows through the quadrupole "belt" forming a ring-shaped hot region on the magnetic equator. In the case (2), magnetic flux in the northern magnetic hemisphere is larger than that in the southern, and the quadrupole belt and the ring are displaced to the south. The stronger the quadrupole, the closer the ring is to the magnetic equator. At sufficiently large misalignment angle $\Theta$, matter also flows to the south pole, forming a hot spot near the pole. The light curves have a variety of different features which makes it difficult to derive the magnetic field configuration from the light curves. There are specific features which are different in cases of dipole and quadrupole dominated magnetic field: (1) Angular momentum flow between the star and disc is more efficient in the case of the dipole field; (2) Hot spots are hotter and brighter in case of the dipole field because the matter accelerates over a longer distance compared with the flow in a quadrupole case.

Journal ArticleDOI
TL;DR: In this paper, the magnitudes and signs of twenty eight E2 and three M1 matrix elements involving 17 low-lying excited states in 104Ru have been measured by Coulomb excitation using 208Pb, 136Xe and 58Ni ions.

Journal ArticleDOI
TL;DR: In this article, a relativistic many-body perturbation method is developed to calculate energy and transition rates for multipole transitions in many-electron ions with nuclear charges ranging from Z = 30 to 100.
Abstract: A relativistic many-body method is developed to calculate energy and transition rates for multipole transitions in many-electron ions. This method is based on relativistic many-body perturbation theory (RMBPT), agrees with MCDF calculations in lowest-order, includes all second-order correlation corrections and includes corrections from negative energy states. Reduced matrix elements, oscillator strengths, and transition rates are calculated for electric-multipole (dipole (E1), quadrupole (E2), and octupole (E3)) and magnetic-multipole (dipole (M1), quadrupole (M2), and octupole (M3)) transitions between 3l5l' excited and ground states in Ni-like ions with nuclear charges ranging from Z = 30 to 100. The calculations start from a 1s22s22p63s23p63d10} Dirac-Fock potential. First-order perturbation theory is used to obtain intermediate-coupling coefficients, and second-order RMBPT is used to determine the matrix elements. A detailed discussion of the various contributions to the dipole matrix elements and energy levels is given for nickellike tungsten (Z = 74). The contributions from negative-energy states are included in the second-order E1, M1, E2 M2, E3, and M3 matrix elements. The resulting transition energies and transition rates are compared with experimental values and with results from other recent calculations. These atomic data are important in modeling of M-shell radiation spectra of heavy ions generated in electron beam ion trap experiments and in M-shell diagnostics of plasmas.

Journal ArticleDOI
TL;DR: In this article, the magnetic and thermodynamic properties of PrMg 3 single crystals were investigated based on the magnetic susceptibility χ( T ) and the specific heat C P ( T ).
Abstract: The magnetic and thermodynamic properties of PrMg 3 single crystals were investigated based on the magnetic susceptibility χ( T ) and the specific heat C P ( T ). An observed broad anomaly in C P ( T ) with a peak ∼1.8 J/(mol K) at 0.9 K, together with Van-Vleck-like behavior of χ( T ), indicates that the low- T properties are ascribed to the multipole (quadrupole O 20 and O 22 , and octupole T x y z ) degrees of freedom of a nonmagnetic, non-Kramers Γ 3 doublet ground state in the cubic crystalline electric field of Pr 3+ . The low- T C P ( T ) anomaly, however, is not described in terms of the two-channel Kondo model, but is more similar to that for the single-channel Kondo model with the Kondo temperature T K = 1.3 K, including its weak external-field dependence. No evidence for a cooperative phase transition was detected down to 0.54 K in C P ( T ), suggesting that the Γ 3 multipole degrees of freedom are quenched at low T by forming a strongly correlated electronic state through the hybridization wit...

Journal ArticleDOI
TL;DR: The object here is to demonstrate that the SSDQO potentialEnergy function can accurately mimic the potential energy function of a multipoint model using the moments of that model, and the contribution of each moment to the energetics and other properties can be determined.
Abstract: A new, efficient potential energy function for liquid water is presented here. The new model, which is referred here as the soft sticky dipole-quadrupole-octupole (SSDQO) model, describes a water molecule as a Lennard-Jones sphere with point dipole, quadrupole, and octupole moments. It is a single-point model and resembles the hard-sphere sticky dipole potential model for water by Bratko et al. [J. Chem. Phys. 83, 6367 (1985)] and the soft sticky dipole model by Ichiye and Liu [J. Phys. Chem. 100, 2723 (1996)] except now the sticky potential consists of an approximate moment expansion for the dimer interaction potential, which is much faster than the true moment expansion. The object here is to demonstrate that the SSDQO potential energy function can accurately mimic the potential energy function of a multipoint model using the moments of that model. First, the SSDQO potential energy function using the dipole, quadruple, and octupole moments from SPC/E, TIP3P, or TIP5P is shown to reproduce the dimer pote...

Journal ArticleDOI
TL;DR: It is found that a quadrupole with an added hexapole field in the range 2–12% can provide mass analysis provided the dc is applied with the correct polarity and value.

Reference EntryDOI
Dieter Freude1
15 Sep 2006
TL;DR: In this paper, the line shape for first and second-order quadrupole broadened spectra with and without magic-angle spinning (MAS) of the powder, the most important experimental techniques for the study of quadrupolar nuclei with half-integer spins such as DOR, dynamic-angles spinning (DAS), MQMAS, echo and nutation techniques, and some recent developments in deuterium NMR.
Abstract: Solid-state nuclear magnetic resonance (NMR) spectroscopy is mostly applied to 1H or 13C nuclei with the nuclear spin , but about 100 of 130 NMR isotopes have , and the electric quadrupole interaction strongly broadens the NMR signal in the solid-state powder spectra. The perturbing effect of the electric quadrupole interaction is reduced at the higher magnetic fields which are available at present. In addition, approaches of the solid-state NMR traditionally used in the study of spin- nuclei have been adapted for use with quadrupolar nuclei, and some techniques, e.g. double-rotation (DOR) and multiple-quantum transition in combination with fast spinning [multiple-quantum magic-angle spinning (MQMAS)], were recently developed for quadrupolar nuclei with half-integer spins. This article describes the basic theory, the line shape for first- and second-order quadrupole broadened spectra with and without magic-angle spinning (MAS) of the powder, the most important experimental techniques for the study of quadrupolar nuclei with half-integer spins such as DOR, dynamic-angle spinning (DAS), MQMAS, echo and nutation techniques, and some recent developments in deuterium NMR. Electric field gradient and chemical shift data for the most commonly studied quadrupolar nuclei with half-integer spins, 27Al, 23Na, and 17O, and a few references to recent solid-state NMR studies of some other quadrupolar nuclei are given.

Journal ArticleDOI
TL;DR: The inclusion of the quadrupolar term in the equation of state therefore reduces the need to use effective parameters by explicitly including at the molecular level interactions due to the quadruplerupole moment.
Abstract: The phase behavior of nitrogen + n-alkanes is studied within the framework of the statistical associating fluid theory for potentials of variable range (SAFT-VR). The effect of the quadrupole moment of nitrogen on the phase behavior is considered through an extension of the SAFT-VR equation that includes an additional contribution to the Helmholtz free energy due to quadrupolar interactions. A significant improvement in the description of the phase diagram of the binary mixtures of nitrogen with different n-alkanes is obtained with the new approach when compared to predictions from the original SAFT-VR EOS (i.e., without the quadrupolar term). The experimental value for the quadrupole moment of nitrogen is used in the new equation; thus, no additional parameters are employed. Given the nonideal nature of the binary mixtures, a binary interaction parameter is needed to describe the full-phase diagram and high-pressure critical lines of these systems; however, this can be fitted to a single system and successfully used to predict the phase behavior of other binary mixtures without additional fitting. Furthermore, only a single, transferable, cross-energy parameter is required when the quadrupolar term is considered, whereas a cross-range parameter is also needed with the original SAFT-VR approach. The inclusion of the quadrupolar term in the equation of state therefore reduces the need to use effective parameters by explicitly including at the molecular level interactions due to the quadrupole moment.

Journal ArticleDOI
TL;DR: The ion motion in such an electric field is derived, and the stability of ions is presented in the a-q diagram that is commonly used for sinusoidal wave quadrupole mass spectrometry in association with the solution of the Mathieu equation.
Abstract: A quadrupolar electric field driven by a rectangular wave voltage can be used for mass-selective storage and analysis. The ion motion in such an electric field is derived, and the stability of ions is presented in the a-q diagram that is commonly used for sinusoidal wave quadrupole mass spectrometry in association with the solution of the Mathieu equation. The pseudo-potential well is discussed in an approximation that leads to the relation of secular frequency to operating parameters. A scheme for a digital ion trap mass spectrometer is described, based on this theory. An ion optics simulation was performed to check the theory of resonant ejection, and to prove the feasibility of the mass scan method for a practical ion trap of such geometry. Copyright © 2005 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: The results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios at W = 1232 MeV were obtained using the magnetic spectrometers of the A1 Collaboration at MAMI as mentioned in this paper.
Abstract: To determine nonspherical angular-momentum amplitudes in hadrons at long ranges (low Q 2 ), data were taken for the p(~e 0 p)… 0 reaction in the ¢ region at Q 2 = 0:060 (GeV/c) 2 utilizing the magnetic spectrometers of the A1 Collaboration at MAMI. The results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios at W = 1232 MeV are M

Journal ArticleDOI
TL;DR: In this article, a four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole, and hexapole field to create a double-well or a donut-shaped trapping field.
Abstract: A four electrode electrostatic trap geometry is demonstrated that can be used to combine a dipole, quadrupole, and hexapole field. A cold packet of $^{15}\mathrm{ND}_{3}$ molecules is confined in both a purely quadrupolar and hexapolar trapping field and additionally, a dipole field is added to a hexapole field to create either a double-well or a donut-shaped trapping field. The profile of the $^{15}\mathrm{ND}_{3}$ packet in each of these four trapping potentials is measured, and the dependence of the well-separation and barrier height of the double-well and donut potential on the hexapole and dipole term are discussed.

Journal ArticleDOI
TL;DR: In this paper, the parity splitting and electric dipole, quadrupole, and octupole transition moments of heavy nuclei are calculated within a cluster model based on the assumption that reflection asymmetric shapes are produced by the motion of the nuclear system in the mass asymmetry coordinate.
Abstract: The low-lying alternative parity bands in heaviest nuclei are predicted for the first time The parity splitting and electric dipole, quadrupole, and octupole transition moments of heavy nuclei are calculated within a cluster model The model is based on the assumption that reflection asymmetric shapes are produced by the motion of the nuclear system in the mass asymmetry coordinate

Journal ArticleDOI
TL;DR: In this paper, a linear list for the ammonia molecule and its three deuterated variants NH 2 D, ND 2 H, and ND 3 was built taking hyperfine quadrupole coupling effects into account.
Abstract: Linelists for the ammonia molecule and its three deuterated variants NH 2 D, ND 2 H, and ND 3 are built taking hyperfine quadrupole coupling effects into account For each hyperfine component, the line frequency, the line intensity, and the lower level energy are calculated

Journal ArticleDOI
01 Jul 2006
TL;DR: A simple formula is derived for the free solution electrophoretic mobility of protein by including both molecular shape and charge distribution effects, which predicts correctly the hydrodynamic radius of protein from the atomic coordinate data.
Abstract: We derive a simple formula for the free solution electrophoretic mobility of protein by including both molecular shape and charge distribution effects. The molecular shape of protein is described by a deformed sphere model, while the charge distribution is represented in terms of net charge, charge dipole, and charge quadrupole. The deformed sphere model approximates the radial coordinate of the protein surface as a simple quadratic equation based on the atomic coordinate data. Charge dipole does not affect the mobility of protein. Combined with the quadratic coefficients of the surface equation, charge quadrupole affects the mobility. When the charge quadrupole contribution is negligible, the mobility equation simplifies to the Henry equation in which the sphere radius is replaced with the hydrodynamic radius of protein. The deformed sphere model predicts correctly the hydrodynamic radius of protein from the atomic coordinate data. The hydrodynamic radius is not the radius of sphere of equal volume but the effective radius that correlates with the translational diffusivity of protein. To illustrate the utility of our mobility equation we study the electrophoresis of lysozyme and compare our results with previously published works.

Journal ArticleDOI
TL;DR: In this article, the authors present a formalism for calculating the correlation function of remote quadrupole measurements in spherical harmonic space, along with the length scales probed by these modes.
Abstract: Scattering of cosmic microwave background (CMB) radiation in galaxy clusters induces a polarization signal proportional to the CMB quadrupole anisotropy at the cluster's location and lookback time. A survey of such remote quadrupole measurements provides information about large-scale cosmological perturbations. This paper presents a formalism for calculating the correlation function of remote quadrupole measurements in spherical harmonic space. The number of independent modes probed by both single-redshift and volume-limited surveys is presented, along with the length scales probed by these modes. In a remote quadrupole survey sparsely covering a large area of sky, the largest-scale modes probe the same-length scales as the quadrupole but with much narrower Fourier-space window functions. The largest-scale modes are significantly correlated with the local CMB, but even when this correlation is projected out the largest remaining modes probe gigaparsec scales (comparable to the CMB at $l=2\mathrm{\text{\ensuremath{-}}}10$) with narrow window functions. These modes may provide insight into the possible anomalies in the large-scale CMB anisotropy. At fixed redshift, the data from such a survey form an $E$-type spin-2 field on the sphere to a good approximation; the near absence of $B$ modes will provide a valuable check on systematic errors. A survey of only a few low-redshift clusters allows an independent reconstruction of the five coefficients of the local CMB quadrupole, providing a test for contamination in the Wilkinson Microwave Anisotropy Probe quadrupole. The formalism presented here is also useful for analyzing smaller-scale surveys to probe the late integrated Sachs-Wolfe effect and hence the properties of dark energy.