Ultrafast Temporal Evolution of Interatomic Coulombic Decay in NeKr Dimers

We investigate interatomic Coulombic decay in NeKr dimers after neon inner-valence photoionization [Ne+(2s-1)] using a synchrotron light source. We measure with energy resolution the two singly charged ions of the...

Вероятность ионизации атомов, распыленных при бомбардировке поверхности металлов одно- и многозарядными ионами

The processes of ionization of atoms sputtered under bombardment of clean metal surface by singly and multiply charged ions with kinetic energy of several keV were studied. Within the framework of simple phenomenological model of ion formation, the relaxation of local electron excitation in metal was taking into account. Analytical expressions for estimation of ionization probability of sputtered atoms was obtain. It was shown, that in comparison with singly charged ions, bombardment of metals with multiply charged ions results to significant increase of ionization probability of sputtered atoms due to more efficient excitation of electrons and increase of relaxation time of this excitation.

Detailed dynamics of direct three-body recombination of singly charged ions

We consider the main aspects of detailed dynamics of the reactions of direct three-body ion-ion recombination Cs+ + X– + R → CsX + R (X– = F–, I– and...

THE INFLUENCE OF SINGLY CHARGED IONS ON THE TRANSLATIONAL MOTION OF MOLECULES IN EXTREMELY DILUTE AMIDE SOLUTIONS

The type of short range solvation of Li+, Na+ K+, Rb+, Cs+, NH4+, Cl– , Br–, I–, ClO4– ions has been determined and analyzed in formamide (FA), N-methylformamide (MFA), N-dimethylformamide (DMF) at 298.15 K. In order to determine the type of ion solvation we used familiar-variable quantitative parameter (– ri), where is the translational displacement length of ion, ri is its structural radius. It was found that the difference (– ri) is equal to the coefficient of attraction friction (CAF) of ions normalized to the solvent viscosity and hydrodynamic coefficient. The sign of the CAF is determined by the sign of the algebraic sum of its ion-molecular and intermolecular components. In amide solutions the studied cations are cosmotropes (positively solvated ((– ri) > 0), structure-making ions) and anions are chaotropes (negatively solvated ((– ri) < 0 ), structure-breaking ions). In the amide series, regardless of the sign (– ri), the near-solvation enhances, which can be explained by the weakening of the specific interaction between the solvent molecules. The decrease of and respectively (– ri) with increasing cation radius in a given solvent is the result of weakening of its coordinating force due to the decrease of charge density in the series Li+–Na+–K+–Rb+–Cs+. The increase of (and (– ri), correspondingly) for the ions studied in the series FA- MFA-DMF can be explained by the weakening of intermolecular interactions in this series, which leads to the strengthening of solvation. It was found that for the halide ions in the series FA-MFA-DMF the regular growth of parameter is explained by the weakening of the solvent structure. It was shown that Li+ ion with the lowest diffusion coefficient among cations and the highest value forms kinetically stable complexes in amide solutions.

Dynamical evolution and decay of multi-charged quantum vortex in a Bose–Einstein condensate

We report the observation of the twisted decay of quadruply charged vortices taking place in an atomic Bose–Einstein condensate. Supporting numerical simulations show that the singly-charged vortices, which result from the decay of a multi-charged vortex, twist around intertwined in the shape of helical Kelvin waves.

Low-Energy Ion Transport Between Two Insulating Parallel Plates

Experimental data are presented for low-energy singly charged ion transport between two insulating parallel plates. Using a beam intensity of approximately 20 pA, measurements of the incoming and transmitted beams provide quantitative temporal information about the charge deposited on the plates and the guiding probability. Using a smaller beam intensity (~1 pA) plate charging and discharging properties were studied as a function of time. These data imply that both the charge deposition and decay along the surface and through the bulk need to be modeled as acting independently rather than as a combined weighted average. A further reduction of beam intensity to ~25 fA allowed temporal imaging studies of the positions and intensities of the guided beam plus two bypass beams to be performed. Because of the parallel plate geometry, SIMION software was used to simulate trajectories of the guided and bypass beams. This provides information about the amount and location of deposited charge and, as a function of charge patch voltage, the probability of beam guiding and how much the bypass beams are deflected. Information about the electric fields which provides insights into the relative charge decay via the surface and bulk is also obtained. An equivalent electric circuit model of the parallel plates is used to associate the deposited charge with the patch voltage. To achieve internal consistency between the various sets of experimental data and the SIMION information, the deposited charge is implied to be distributed primarily on the inner surface of the plates, transverse to the beam direction, rather than being distributed throughout the entire plate.

Determination of the refractive index profile and surface topography of optically smooth objects using interference of optical vortices

In this paper, we present the results of the propagational dynamics of vortex beams in the scope of their possible applications for interferometric non-contact robust and precision optical surface profilometry with nanoscale longitudinal resolution. The result of coaxial superposition of the reference plane wave with singly charged vortex beams represents a dynamically changing intensity distribution. The nature of this changes, namely, rotational effects of intensity zeros, allows to determine directly the optical path difference which is introduced by the surfaces and internal structure of test object. We have proposed the experimental setup for examination of reflecting and transmitting objects.

Vector-like quarks decaying into singly and doubly charged bosons at LHC

We investigate the production of vector-like quarks with charge 5/3 at the LHC and their subsequent decays into new singly or doubly charged bosons plus a heavy quark (top or bottom). In particular, we explore final states with same-sign di-leptons (electron or muon pairs), with the leptons coming from the decay of the new bosons and, in the case of production of singly charged bosons, from top quarks as well. These processes are predicted by classes of models based on extensions of the gauge group of the Standard Model, such as the 331 Model, where the electroweak symmetry is described by SU(3)L × U(1)X, X being a new abelian charge. For this purpose, a CMS search for vector-like partners with charge 5/3 decaying into Wt is recast to obtain model-independent bounds and projected reaches at future luminosity stages of the LHC. The results are then interpreted as mass bounds for the new particles predicted in the 331 Model and as a constraint on the scale of its spontaneous symmetry breaking. The complete set of model-independent results are provided as recast efficiencies, to allow for reinterpretation in different scenarios.