Showing papers on "Quadrupole published in 2003"
TL;DR: In this paper, a new classical empirical potential is proposed for water, which uses a polarizable atomic multipole description of electrostatic interactions, and a modified version of Thole's interaction model is used to damp induction at short range.
Abstract: A new classical empirical potential is proposed for water. The model uses a polarizable atomic multipole description of electrostatic interactions. Multipoles through the quadrupole are assigned to each atomic center based on a distributed multipole analysis (DMA) derived from large basis set molecular orbital calculations on the water monomer. Polarization is treated via self-consistent induced atomic dipoles. A modified version of Thole's interaction model is used to damp induction at short range. Repulsion−dispersion (vdW) effects are computed from a buffered 14−7 potential. In a departure from most current water potentials, we find that significant vdW parameters are necessary on hydrogen as well as oxygen. The new potential is fully flexible and has been tested versus a variety of experimental data and quantum calculations for small clusters, liquid water, and ice. Overall, excellent agreement with experimental and high level ab initio results is obtained for numerous properties, including cluster st...
1,315 citations
TL;DR: As a consequence of the strong dependence of the axial field on radial displacement, trapped thermalized ions can be ejected axially from a linear ion trap in a mass-selective way when their radial amplitude is increased through a resonant response to an auxiliary signal.
204 citations
TL;DR: In this paper, the authors showed that a small antiferromagnetic moment, parallel to [010] (y -direction), is induced in the field-induced phase (H ∥ z ).
Abstract: Neutron diffraction experiments on the heavy-fermion superconductor PrOs 4 Sb 12 revealed that a small antiferromagnetic moment, parallel to [010] ( y -direction), is induced in the field-induced phase ( H ∥ z ). The analysis, based on the Γ 1 singlet ground state crystal field model, shows that antiferro-order of O y z -type quadrupole moments of Pr ions is formed in the field-induced phase. This strongly suggests that the crystal field ground-state of Pr ions in PrOs 4 Sb 12 is the Γ 1 singlet and the quadrupolar ordering is induced due to level crossing with an excited state under a magnetic field.
199 citations
TL;DR: In this paper, it was shown that the low quadrupole amplitude is associated with spatial curvature, and that the quadrupoles amplitude can be reproduced if the primordial spectrum truncates on scales comparable to the curvature scale.
Abstract: The temperature anisotropy power spectrum measured with the Wilkinson Microwave Anisotropy Probe (WMAP) at high multipoles is in spectacular agreement with an inflationary Lambda-dominated cold dark matter cosmology. However, the low order multipoles (especially the quadrupole) have lower amplitudes than expected from this cosmology, indicating a need for new physics. Here we speculate that the low quadrupole amplitude is associated with spatial curvature. We show that positively curved models are consistent with the WMAP data and that the quadrupole amplitude can be reproduced if the primordial spectrum truncates on scales comparable to the curvature scale.
180 citations
TL;DR: In this article, it was shown that the low quadrupole amplitude is associated with spatial curvature and positively curved models are consistent with the WMAP data and can be reproduced if the primordial spectrum truncates on scales comparable to the curvature scale.
Abstract: The temperature anisotropy power spectrum measured with the Wilkinson Microwave Anisotropy Probe (WMAP) at high multipoles is in spectacular agreement with an inflationary Λ-dominated cold dark matter cosmology. However, the low-order multipoles (especially the quadrupole) have lower amplitudes than expected from this cosmology, indicating a need for new physics. Here we speculate that the low quadrupole amplitude is associated with spatial curvature. We show that positively curved models are consistent with the WMAP data and that the quadrupole amplitude can be reproduced if the primordial spectrum truncates on scales comparable to the curvature scale.
167 citations
TL;DR: In this paper, the authors present a review of the review after it was published, showing that some errors were found in this review after the review had been published, such as: gSchmidt(πd3/2) = 0.083 Page 642, paragraph 2.3, line 7 and line 12: g Schmidt = -1.913
Abstract: Some errors were found in this review after it was published. Page 642, line 1: gSchmidt(πd3/2)=0.083 Page 642, paragraph 2.1.3, line 7 and line 12: gSchmidt = -1.913 should read μSchmidt = -1.913 Page 663, expression (4.7) should read: Figure 13 was incorrectly labelled. The correct figure is given below. Figure 13. (a) Zeeman splitting of the nuclear m-quantum levels due to interaction of the nuclear dipole moment (μ = gIμN) with a static magnetic field B. In a classical picture this can be seen as a precession of the spin I around B with a Larmor frequency νL. (b) Non-equidistant quadrupole splitting of the nuclear m-quantum levels due to interaction of the nuclear spectroscopic quadrupole moment Qs with an EFG Vzz. Page 673, expression (5.8) should read:
137 citations
TL;DR: In this article, the Hartree-Fock limit for the mean hyperpolarizability is estimated at γ=715±4e4a04Eh−3 at the experimental bond length Re=2.074 32a0.
Abstract: We report accurate values of the electric moments, static polarizabilities, hyperpolarizabilities and their respective derivatives for N2. Our values have been extracted from finite-field Moller–Pleset perturbation theory and coupled cluster calculations performed with carefully designed basis sets. A large [15s12p9d7f] basis set consisting of 290 CGTF is expected to provide reference self-consistent-field values of near-Hartree–Fock quality for all properties. The Hartree–Fock limit for the mean hyperpolarizability is estimated at γ=715±4e4a04Eh−3 at the experimental bond length Re=2.074 32a0. Accurate estimates of the electron correlation effects were obtained with a [10s7p6d4f] basis set. Our best values are Θ=−1.1258ea02 for the quadrupole and Φ=−6.75ea04 for the hexadecapole moment, ᾱ=11.7709 and Δα=4.6074e2a02Eh−1 for the mean and the anisotropy of the dipole polarizability, C=41.63e2a04Eh−1 for the mean quadrupole polarizability and γ=927e4a04Eh−3 for the dipole hyperpolarizability. The latter v...
133 citations
TL;DR: This work studies the two transverse quadrupole modes of a cigar-shaped Bose-Einstein condensate with a single centered vortex and shows that the counterrotating mode is more strongly damped than in the absence of a vortex, whereas the corotating modes are not affected appreciably by the vortex.
Abstract: We study the two transverse quadrupole modes of a cigar-shaped Bose-Einstein condensate with a single centered vortex. We show that the counterrotating mode is more strongly damped than in the absence of a vortex, whereas the corotating mode is not affected appreciably by the vortex. We interpret this result as a decay of the counterrotating quadrupole mode into two excitations of the vortex line, the so-called Kelvin modes. This is supported by direct observation of the vortex line.
123 citations
TL;DR: In this article, a discrete reaction field model within Density functional theory (DFT) for studying solvent effects on molecules is presented. But the model is not suitable for the case of water in aqueous solution, and it is found that the inclusion of solvent polarization is essential for an accurate description of dipole and quadrupole moments in the liquid phase.
Abstract: In this work we present theory and implementation for a discrete reaction field model within Density Functional Theory (DFT) for studying solvent effects on molecules. The model combines a quantum mechanical (QM) description of the solute and a classical description of the solvent molecules (MM). The solvent molecules are modeled by point charges representing the permanent electronic charge distribution, and distributed polarizabilities for describing the solvent polarization arising from many-body interactions. The QM/MM interactions are introduced into the Kohn–Sham equations, thereby allowing for the solute to be polarized by the solvent and vice versa. Here we present some initial results for water in aqueous solution. It is found that the inclusion of solvent polarization is essential for an accurate description of dipole and quadrupole moments in the liquid phase. We find a very good agreement between the liquid phase dipole and quadrupole moments obtained using the Local Density Approximation and results obtained with a similar model at the Coupled Cluster Singles and Doubles level of theory using the same water cluster structure. The influence of basis set and exchange correlation functional on the liquid phase properties was investigated and indicates that for an accurate description of the liquid phase properties using DFT a good description of the gas phase dipole moment and molecular polarizability are also needed.
98 citations
Patent•
30 May 2003TL;DR: In this paper, a mass spectrometer is configured with individual multipole ion guides, configured in an assembly in alignment along a common centerline, and configured in a six vaccum pumping stage hybrid API source-multiple quadrupole TOF mass analyzer.
Abstract: A mass spectrometer is configured with individual multipole ion guides, configured in an assembly in alignment along a common centerline. A linear (22) of four independent quadrupole ion guides (23, 24, 25, 26) and three smaller quadrupole ion guide segments (39, 40, 41) are positioned along common axis (27) and are configured in a six vaccum pumping stage hybrid API source-multiple quadrupole TOF mass analyzer.
95 citations
TL;DR: This work examines how the results of ab initio electronic structure calculations, based upon planewave DFT methods, on general configurations of ions derived from simulations at finite temperature, may be used to parameterize an "aspherical ion method" (AIM) potential.
Abstract: Oxide potentials which transfer well between different materials have to account explicitly for many-body contributions to the interaction potentials between the ions. These include dipole and quadrupole polarization effects and the compression and deformation of an oxide ion by its immediate coordination environment. Such complex potentials necessarily involve many parameters. We examine how the results of ab initio electronic structure calculations, based upon planewave DFT methods, on general configurations of ions derived from simulations at finite temperature, may be used to parameterize an “aspherical ion method”
(AIM) potential (A. J. Rowley, P. emmer, M. Wilson and P. A. Madden, J. Chem. Phys., 1998, 108, 10 209). Dipoles and quadrupoles on the individual ions are obtained via a transformation of the Kohn–Sham orbitals to localized orbitals on each ion, which enables a distorted charge density for each ion to be obtained. The dipoles and quadrupoles appearing in polarization parts of the AIM potential are fit to those obtained from the ab initio ionic charge densities obtained in this way. The remaining parts of the potential, describing short-range repulsive interactions between ions with compressed and deformed charge densities, are fit to the ab initio forces and the stress tensor. By using a sufficiently large and varied set of configurations on which to carry out this optimization, an excellent transferable potential is obtained.
TL;DR: An overview of the application of lasers in nuclear physics can be found in this paper, where the authors focus on atomic physics techniques for extracting nuclear properties such as the nuclear spin, the magnetic dipole moment, the spectroscopic quadrupole moment and changes in charge radii.
TL;DR: This work represents the first observation of the magneticOctupole moment of the cesium nucleus, and the magnetic dipole a, electric quadrupole b, and magnetic octupole c hyperfine coupling constants are determined.
Abstract: We describe our high-resolution measurements of the 133Cs 6p (2)P(3/2) state hyperfine structure. An optically narrowed diode laser excites perpendicularly a highly collimated atomic beam. The spectra are calibrated with a stable reference diode laser using a rf locking scheme allowing us to determine the splittings with an accuracy of < or =2 kHz, an order of magnitude better than previous results. The magnetic dipole a, electric quadrupole b, and magnetic octupole c hyperfine coupling constants are determined. The values we obtained are a=50.288 27(23) MHz, b=-0.4934(17) MHz, and c=0.56(7) kHz. This work represents the first observation of the magnetic octupole moment of the cesium nucleus. We carry out atomic-structure calculations and determine the nuclear electric quadrupole moment Q= -3.55(4) mb and nuclear magnetic octupole moment Omega=0.82(10) b x mu(N).
TL;DR: The recently introduced Q2-pulsing function, which enhances the transmission of fragment ions of a selected m/z window from the collision cell into the TOF analyzer, improved the sensitivity of product ion scans on the quadrupole/TOF instrument.
Abstract: A triple-quadrupole instrument and a hybrid quadrupole/time-of-flight (TOF) mass spectrometer were compared for the determination of pharmaceutical compounds in water samples. The drugs investigated were the analgesics Ibuprofen, Fenoprofen, Ketoprofen, Naproxen, and Diclofenac. The recently introduced Q2-pulsing function, which enhances the transmission of fragment ions of a selected m/z window from the collision cell into the TOF analyzer, improved the sensitivity of product ion scans on the quadrupole/TOF instrument. The selectivity is much better on quadrupole/TOF systems than on triple quadrupoles because the high resolving power of the reflectron-TOF mass analyzer permits high-accuracy fragment ion selection. This minimizes interferences from environmental matrices and allows acquisition of full spectra for selected analytes with better signal-to-noise characteristics than comparable spectra obtained with a scanned quadrupole. The qualitative information obtained (mass accuracy, resolution and full-scan spectra) by hybrid quadrupole/TOF mass spectrometry allows a more certain identification of analytes in environmental matrices at trace levels. Sample enrichment of water samples was achieved by a solid-phase extraction procedure. Average recoveries for loading 1 L of samples varied from 88 to 110%, and the quantification limits were less than 1.2 ng/L for the triple-quadrupole instrument (in MRM mode) and less than 3 ng/L for the quadrupole/TOF instrument.
TL;DR: In this paper, the rotational spectra of quinoline and isoquinoline have been observed in the centimeter- and millimeter-wave regions, and the ground states of both molecules were determined from Stark effect measurements.
TL;DR: In this article, a systematic study has been carried out with density functional theory of UO 2 L 2 n+ (n = 0 or 2) complexes, enabling a large database of binding energies and geometries to be established that can improve our knowledge and understanding of the bonding between the uranyl ion UO2 2+ and potential ligands or solvent.
Abstract: A systematic study has been carried out with density functional theory of UO 2 L 2 n+ (n = 0 or 2) complexes. Thirty three ligands have been considered, enabling a large database of binding energies and geometries to be established that can improve our knowledge and understanding of the bonding between the uranyl ion UO 2 2+ and potential ligands or solvent. A statistical study has been performed using the database with the twin aims of predicting the coordination energies of new complexes and revealing the dominant bonding parameters. We have shown that it is possible to predict the coordination energy satisfactorily just from the properties of the isolated ligand. However, the statistical analysis is shown to be physically unsound. To develop our understanding of the nature of the uranyl-ligand bond, the coordination energy has been decomposed into several contributions: electrostatic, repulsion, ligand polarization, uranyl polarization, charge transfer from the ligand to the uranyl ion, and inverse charge transfer. It is clear that the electrostatic term cannot be modeled just by the ligand's dipole moment; a multipole development extending at least to the quadrupole moment is necessary. Our quantitative analysis also shows that the polarization and charge-transfer terms are important and must be included in any force field if numerically and physically reliable results are sought.
TL;DR: In this paper, a comprehensive description of chemical mass shifts in the RF quadrupole ion trap (Paul trap) is given and their origin is explained, extending a previously proposed model, and it is shown that chemical mass shift are a result of an ejection delay caused by field imperfections in RF ion traps with non-optimized geometry, in particular, field defects resulting from holes in the end-cap electrodes, and of compound-dependent modifications of this ejectiondelay by collisions of the ions with the buffer gas.
TL;DR: In this article, it was shown that quadrupole motion produces monopole oscillations in all atomic nuclei, which can be interpreted as a large coupling between one and two phonon states leading to strong anharmonicities.
Abstract: We have performed time dependent Hartree-Fock calculations on the nonlinear response of nuclei. We have shown that quadrupole (and dipole) motion produces monopole (and quadrupole) oscillations in all atomic nuclei. We have shown that these findings can be interpreted as a large coupling between one and two phonon states leading to strong anharmonicities.
TL;DR: These rod sets may offer improved trap performance while still being capable of providing conventional mass analysis, and are unexpected in view of the literature that argues that to obtain high mass resolution with quadrupole mass filters, higher order multipoles must be kept as small as possible.
Abstract: The performance of quadrupole mass filters with added octopole fields in the range 2.0-4.0% has been investigated. The added fields are much greater than those normally added to conventional rod sets by mechanical tolerances or construction errors. Quadrupole rod sets with added octopole fields were constructed with round rods by making one pair of rods greater in diameter than the other pair. For positive ions, resolution at half height of only about 200 is possible if the negative direct current (dc) output of the quadrupole power supply is connected to the smaller rods. If the positive dc output of the quadrupole power supply is connected to the smaller rods, the resolution improves dramatically; a resolution at half height of 5800 has been observed with a rod set with 2.6% added octopole field. For negative ions the best resolution is obtained with the polarity of the dc reversed, i.e. with the negative dc applied to the smaller rods. These findings are unexpected in view of the literature that argues that to obtain high mass resolution with quadrupole mass filters, higher order multipoles must be kept as small as possible. Numerical simulations of peak shapes agree qualitatively with experiments. Simulation of the boundaries of the first stability region for positive ions shows that when the positive dc is applied to the smaller rods, the addition of a 2.0% octopole field causes the boundaries to shift slightly but the boundaries are well defined, and the tip of the stability region remains sharp. When the positive dc is applied to the larger rods, the boundaries of the stability region move out and become diffuse. For instruments that require a rod set that can be used both as a linear trap and a mass filter, these rod sets may offer improved trap performance while still being capable of providing conventional mass analysis.
TL;DR: In this paper, the effect of deformation on the compressional-mode giant resonances was investigated for five Sm isotopes with 386-MeV a particles at forward angles (including 0degrees).
Abstract: Background-free inelastic scattering spectra have been obtained for five Sm isotopes with 386-MeV a particles at forward angles (including 0degrees) to investigate the effect of deformation on the compressional-mode giant resonances. The strength distributions for the Lless than or equal to3 isoscalar giant resonances have been extracted via a multipole decomposition analysis using angular distributions calculated in the framework of the density-dependent single-folding model. We observed a splitting of the giant monopole resonance because of its mixing with the giant quadrupole resonance. For the isoscalar giant dipole resonance, the observed effects of deformation are different for the low- and high-excitation-energy components. Evidence has been obtained for the theoretically predicted mixing between the isoscalar giant dipole resonance and the high energy octupole resonance.
TL;DR: In this paper, the dipole and electric quadrupole excitations in 204,206,207,208 Pb have been measured up to 6.75 MeV in resonant photon scattering experiments at the superconducting Darmstadt electron linear accelerator S-DALINAC using two Euroball-Cluster detector modules.
Patent•
10 Feb 2003
TL;DR: In this paper, a triple quadrupole mass spectrometer is used for analyzing mixtures of substances using a triple ionization process, in which the mixture of substances are ionized prior to analysis.
Abstract: The invention relates to a mass spectrometry method for analysing mixtures of substances using a triple quadrupole mass spectrometer, whereby said mixtures of substances are ionised prior to analysis. The invention is characterised in that the method comprises the following steps: a) selection of a mass/charge quotient (m/z) of an ion created by ionisation in a first analytical quadrupole (I) of the mass spectrometer; b) fragmentation of the ion selected in step (a) by applying an acceleration voltage in an additional subsequent quadrupole (II), which is filled with a collision gas and acts as a collision chamber; c) selection of a mass/charge quotient of an ion created by the fragmentation process in step (b) in an additional subsequent quadrupole (III), whereby steps (a) to (c) of the method are carried out at least once; and d) analysis of the mass/charge quotients of all the ions present in the mixture of substances as a result of the ionisation process, whereby the quadrupole (II) is filled with collision gas, but no acceleration voltage is applied during the analysis. Steps (a) to (c) and step (d) can also be carried out in reverse order.
TL;DR: In this paper, it was shown that small transverse magnetic quadrupole fields sharply degrade the confinement of non-neutral plasmas held in Malmberg-Penning traps.
Abstract: Small transverse magnetic quadrupole fields sharply degrade the confinement of non-neutral plasmas held in Malmberg-Penning traps. For example, a quadrupole magnetic field of only $0.02\text{ }\mathrm{G}/\mathrm{c}\mathrm{m}$ doubles the diffusion rate in a trap with a 100 G axial magnetic field. Larger quadrupole fields noticeably change the shape of the plasma. The transport is greatest at an orbital resonance. These results cast doubt on plans to use magnetic quadrupole neutral atom traps to confine antihydrogen atoms created in double-well positron/antiproton Malmberg-Penning traps.
TL;DR: In this paper, the authors describe a new technology for superconducting quadrupole magnets especially for use in particle accelerators, based on the application of a sinusoidal modulation to the axial positions of the conductor windings in solenoids.
Abstract: We describe a new technology for superconducting quadrupole magnets especially for use in particle accelerators. The principle is based on the application of a sinusoidal modulation to the axial positions of the conductor windings in solenoids. The method can also be employed to produce higher-order multipole fields. Due to their solenoid-like geometry, these coils are significantly simpler to manufacture than standard (racetrack) cosine-2-theta coils and have significantly smaller systematic field errors without using any field-shaping spacers. When two complementary coil layers (with opposite current flow) are combined, the solenoid components of the fields are cancelled and the quadrupole or higher-order fields add. An example of such a design is described which generates a gradient of 130 T/m with systematic errors less than 10/sup -8/ at 67% of the aperture.
TL;DR: In this article, the relativistic multireference many-body perturbation theory was applied to the ground and over 80 low-lying odd-and even-parity excited states of multi-valence-electron ions.
Abstract: Energies of the ground and a number of even- and odd-parity excited states of multi-valence-electron ions have been computed by a computational method in the framework of relativistic multireference many-body perturbation theory Relativistic multireference perturbation calculations are reported for the ground and over 80 low-lying odd- and even-parity excited states of siliconlike argon (Ar{sup 4+}) and aluminumlike iron (Fe{sup 13+}) to demonstrate the unprecedented accuracy of the method The theory deviates from experiment by less than 02% for all but a few excited levels in siliconlike argon For the more highly ionized aluminumlike iron, the deviations are reduced to within 006% Theoretical magnetic dipole and electric quadrupole transition rates of the lowest-lying {sup 2}P{sub 3/2}{sup o} state of aluminumlike Fe and Mn are evaluated, and lifetimes are compared with a recent ion trap experiment
TL;DR: The phase transition at T0 = 25 K in NpO2 and the single-ion nature of the Np 5f electrons is examined in the light of the results of resonant x-ray scattering experiments at the M4 Np edge.
Abstract: The phase transition at T0 = 25 K in NpO2 and the single-ion nature of the Np 5f electrons is examined in the light of the results of resonant x-ray scattering experiments at the M4 Np edge. These experiments exclude usual magnetic dipole ordering at T0, and provide direct evidence of long-range order of the electric quadrupole moment with ?5 symmetry. The phase transition is purely electronic and does not involve either internal or external crystallographic distortions, so the symmetry of the system remains cubic. The primary order parameter (OP) is associated with ?4t magnetic octupoles, ordering in a triple-q longitudinal structure defined by the three wavevectors of the 001 star. Magnetic octupolar order breaks invariance under time reversal and induces the order of electric quadrupoles as the secondary OP. The resulting ground state is a singlet with zero dipole magnetic moment.
TL;DR: In this article, it was shown that the electric field gradient at the copper nucleus in CuCl is incorrectly described by most of the density functionals currently in use, including gradient corrected and hybrid versions of DFT.
Abstract: In a previous paper [J. Chem. Phys. 111, 3357 (1999)] we showed that the electric field gradient at the copper nucleus in CuCl is incorrectly described by most of the density functionals currently in use, including gradient corrected and hybrid versions of DFT. Here we analyze whether this error is systematic or not by comparing DFT electric field gradients for a number of diatomic compounds MX. The molecules chosen include representatives from early transition metal compounds, ScX, from late transition metal compounds, CuX, and from main group compounds, GaX, where X=F, Cl, Br, I, H and Li. From experimental nuclear quadrupole coupling data and electric field gradient calculations for each of the three sets (ScX, CuX and GaX) the nuclear quadrupole moment at the metal can be deduced at a specific DFT level. It is demonstrated that density functionals work well for main group compounds (GaX), but contain large systematic errors for transition metals such as copper. This leads to unreasonable copper nuclea...
TL;DR: In this paper, the authors demonstrate that a narrow energy profile of the Bragg intensity at the Np?M4 edge is consistent with magnetic and charge contributions to the E1 Bragg amplitude described by Np 5f multipoles of ranks 3 (octupole) and 4 (hexadecapole).
Abstract: The phase transition in NpO2 at T0 ? 25.5 ?K is accompanied by the onset of superlattice reflections in the x-ray Bragg diffraction pattern, with intensity enhanced by an electric dipole (E1) event. Additional experiments using other techniques indicate no ordering at T0 of Np magnetic moments. Absence of long-range magnetic order below T0 fits with the outcome of a polarization analysis of superlattice intensities at 12 K; signals are observed in both the unrotated (?'?) and rotated (?'?) channels of scattering while magnetic (dipole) moments would contribute only in the rotated channel. We demonstrate that these empirical findings, together with a narrow energy profile of the Bragg intensity at the Np?M4 edge, are consistent with magnetic and charge contributions to the E1 Bragg amplitude described by Np 5f multipoles of ranks 3 (octupole) and 4 (hexadecapole). Key to our understanding of the x-ray diffraction data gathered in the vicinity of the Np?M4 edge is recognition of an exchange field creating 3d3/2 core-level structure. The particular importance of the exchange field at the Np?M4 edge is emphatically revealed in calculations of the corresponding x-ray absorption spectrum with and without the core?valence interaction. From the experimental information about NpO2 we can infer a ground-state wavefunction for the Np?5f3 valence shell and estimate saturation values for the octupole and hexadecapole. We are led to null values for Np multipoles of ranks 2 (quadrupole) and 5 (triakontadipole).
TL;DR: The microwave spectrum of o-chlorotoluene has been investigated using molecular beam Fourier transform microwave (MB-FTMW) spectrometers in the frequency range of 4-23 GHz as mentioned in this paper.
TL;DR: Low-lying collective modes of an elongated 87Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing wave along the axial direction are studied.
Abstract: We study low-lying collective modes of an elongated 87Rb condensate produced in a 3D magnetic harmonic trap with the addition of a 1D periodic potential which is provided by a laser standing wave along the axial direction. While the transverse breathing mode remains unperturbed, quadrupole and dipole oscillations along the optical lattice are strongly modified. Precise measurements of the collective mode frequencies at different heights of the optical barriers provide a stringent test of the theoretical model recently introduced [M. Kramer, Phys. Rev. Lett. 88, 180404 (2002)]].