SEARCH FOR STABILITY REGIONS IN THE SPACE OF COEFFICIENTS IN A PENNING-MALMBERG-SURKO TRAP WITH A ROTATING ELECTRIC QUADRUPOLE FIELD

In contrast to the canonically conjugate variates q, p representing the position and momentum of a particle in the phase space distributions, the three Cartesian components, Jx, Jy, Jz of a spin-j system constitute the mutually non-commuting variates in the quasi-probabilistic spin distributions. It can be shown that a univariate spin distribution is never squeezed and one needs to look into either bivariate or trivariate distributions for signatures of squeezing. Several such distributions result if one considers different characteristic functions or moments based on various correspondence rules. As an example, discrete probability distribution for an arbitrary spin-1 assembly is constructed using Wigner-Weyl and Margenau-Hill correspondence rules. It is also shown that a trivariate spin-1 assembly resulting from the exposure of nucleus with non-zero quadrupole moment to combined electric quadrupole field and dipole magnetic field exhibits squeezing in certain cases.

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Mass-selective removal of ions from Paul traps using parametric excitation

Applied Physics B ◽

10.1007/s00340-020-07491-8 ◽

2020 ◽

Vol 126 (11) ◽

Author(s):

Julian Schmidt ◽

Daniel Hönig ◽

Pascal Weckesser ◽

Fabian Thielemann ◽

Tobias Schaetz ◽

...

Keyword(s):

Parametric Excitation ◽

Ion Trap ◽

Paul Trap ◽

Electric Quadrupole ◽

Linear Increase ◽

Selective Removal ◽

Ion Trapping ◽

Secular Frequency ◽

Quadrupole Field ◽

Narrow Bandwidth

AbstractWe study a method for mass-selective removal of ions from a Paul trap by parametric excitation. This can be achieved by applying an oscillating electric quadrupole field at twice the secular frequency $$\omega _{\text {sec}}$$ ω sec using pairs of opposing electrodes. While excitation near the resonance with the secular frequency $$\omega _{\text {sec}}$$ ω sec only leads to a linear increase of the amplitude with excitation duration, parametric excitation near $$2\, \omega _{\text {sec}}$$ 2 ω sec results in an exponential increase of the amplitude. This enables efficient removal of ions from the trap with modest excitation voltages and narrow bandwidth, therefore, substantially reducing the disturbance of ions with other charge-to-mass ratios. We numerically study and compare the mass selectivity of the two methods. In addition, we experimentally show that the barium isotopes with 136 and 137 nucleons can be removed from small ion crystals and ejected out of the trap while keeping $$^{138}\text {Ba}^{+}$$ 138 Ba + ions Doppler cooled, corresponding to a mass selectivity of better than $$\Delta m / m = 1/138$$ Δ m / m = 1 / 138 . This method can be widely applied to ion trapping experiments without major modifications since it only requires modulating the potential of the ion trap.

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A new method of producing an electric quadrupole field

International Journal of Mass Spectrometry and Ion Physics ◽

10.1016/0020-7381(77)83008-8 ◽

1977 ◽

Vol 24 (1) ◽

pp. 107-118 ◽

Cited By ~ 23

Author(s):

H. Matsuda ◽

T. Matsuo

Keyword(s):

Electric Quadrupole ◽

New Method ◽

Quadrupole Field

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A Magnetic Spectrometer for a Scanning Transmission Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052195 ◽

1974 ◽

Vol 32 ◽

pp. 436-437

Author(s):

A. Kosiara ◽

J. W. Wiggins ◽

M. Beer

Keyword(s):

Scanning Transmission Electron Microscope ◽

Magnetic Spectrometer ◽

Fringe Field ◽

Curvature Radius ◽

Magnetic Pole ◽

Quadrupole Field ◽

Transmission Electron ◽

Scanning Transmission ◽

Under Construction ◽

Image Position

A magnetic spectrometer to be attached to the Johns Hopkins S. T. E. M. is under construction. Its main purpose will be to investigate electron interactions with biological molecules in the energy range of 40 KeV to 100 KeV. The spectrometer is of the type described by Kerwin and by Crewe Its magnetic pole boundary is given by the equationwhere R is the electron curvature radius. In our case, R = 15 cm. The electron beam will be deflected by an angle of 90°. The distance between the electron source and the pole boundary will be 30 cm. A linear fringe field will be generated by a quadrupole field arrangement. This is accomplished by a grounded mirror plate and a 45° taper of the magnetic pole.

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The Deformation Structure of the Nuclei 32S and 36Ar

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v13i2.6028 ◽

2017 ◽

Vol 13 (2) ◽

pp. 4678-4688

Author(s):

K. A. Kharroube

Keyword(s):

Single Particle ◽

Electric Quadrupole ◽

Quadrupole Moments ◽

Moments Of Inertia ◽

Deformation Structures ◽

Particle Potential ◽

Nilsson Model ◽

Single Particle Potential ◽

Axes Of Symmetry ◽

Good Agreement

We applied two different approaches to investigate the deformation structures of the two nuclei S32 and Ar36 . In the first approach, we considered these nuclei as being deformed and have axes of symmetry. Accordingly, we calculated their moments of inertia by using the concept of the single-particle SchrÃ¶dinger fluid as functions of the deformation parameter Î². In this case we calculated also the electric quadrupole moments of the two nuclei by applying Nilsson model as functions of Î². In the second approach, we used a strongly deformed nonaxial single-particle potential, depending on Î² and the nonaxiality parameter Î³ , to obtain the single-particle energies and wave functions. Accordingly, we calculated the quadrupole moments of S32 and Ar36 by filling the single-particle states corresponding to the ground- and the first excited states of these nuclei. The moments of inertia of S32 and Ar36 are then calculated by applying the nuclear superfluidity model. The obtained results are in good agreement with the corresponding experimental data.

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Full Optical Rotation Tensor at CCSD Level in the Modified Velocity Gauge

10.26434/chemrxiv.13204064.v2 ◽

2020 ◽

Author(s):

Kaihua Zhang ◽

Ty Balduf ◽

Marco Caricato

Keyword(s):

Electric Dipole ◽

Optical Rotation ◽

Electric Quadrupole ◽

Polarizability Tensor ◽

Dipole Polarizability ◽

Difficult Case ◽

Computationally Efficient ◽

Rotation Tensor ◽

Approximate Methods ◽

Velocity Gauge

<div> <div> <p> </p><div> <div> <div> <p>This work presents the first simulations of the full optical rotation (OR) tensor at coupled cluster with single and double excitations (CCSD) level in the modified velocity gauge (MVG) formalism. The CCSD-MVG OR tensor is origin independent, and each tensor element can in principle be related directly to experimental measurements on oriented systems. We compare the CCSD results with those from two density functionals, B3LYP and CAM-B3LYP, on a test set of 22 chiral molecules. The results show that the functionals consistently overestimate the CCSD results for the individual tensor components and for the trace (which is related to the isotropic OR), by 10-20% with CAM-B3LYP and 20-30% with B3LYP. The data show that the contribution of the electric dipole-magnetic dipole polarizability tensor to the OR tensor is on average twice as large as that of the electric dipole-electric quadrupole polarizability tensor. The difficult case of (1S,4S)-(–)-norbornenone also reveals that the evaluation of the former polarizability tensor is more sensitive than the latter. We attribute the better agreement of CAM-B3LYP with CCSD to the ability of this functional to better reproduce electron delocalization compared with B3LYP, consistently with previous reports on isotropic OR. The CCSD-MVG approach allows the computation of reference data of the full OR tensor, which may be used to test more computationally efficient approximate methods that can be employed to study realistic models of optically active materials. </p> </div> </div> </div> </div> </div>

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