Search results for " Atomic"
showing 10 items of 1098 documents
Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by different…
2015
A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ((196)Hg, (198)Hg, (202)Hg, (204)Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope (204)Hg in…
Optimization of operating conditions of axially and radially viewed plasmas for the determination of trace element concentrations from ultrasound-ass…
2006
Abstract The method of ultrasound-assisted extraction followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of trace element concentrations (arsenic, copper, lead, antimony, and zinc) in shooting range areas was optimized. Optimization was achieved not only on the basis of the analysis of appropriate standard reference materials but also on that of 31 synthetic mixtures of matrix and analyte elements (aluminum, antimony, arsenic, calcium, copper, lead, iron, manganese, silicon, and zinc), in five concentrations. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg II 280.270 nm/Mg I 285.213 …
Investigation of TiO<sub>2</sub> Ceramic Surface Conductivity Using Conductive Atomic Force Microscopy
2012
Dense TiO2 (rutile) ceramic samples were prepared by sintering compacts of titanium dioxide anatase powder at 1500 °C for 5h. Sintered samples were polished and annealed in vacuum at 1000 °C for 1h. Structural properties of the samples were studied by X-ray diffraction, polarized light and scanning electron microscopy. The surface topography and local electrical conductivity of the samples were investigated by atomic force microscopy technique under atmospheric conditions. Enhanced electrical conductivity was observed at grain boundaries while the polished, vacuum annealed grains surface showed non-homogeneous conductivity.
Symmetry and models of single-walled TiO2 nanotubes with rectangular morphology
2011
Abstract The formalism of line symmetry groups for one-periodic (1D) nanostructures with rotohelical symmetry has been applied for symmetry analysis of single-walled titania nanotubes (SW TiO2 NTs) formed by rolling up the stoichiometric two-periodic (2D) slabs of anatase structure. Either six- or twelve-layer (101) slabs have been cut from TiO2 crystal in a stable anatase phase. After structural optimization, the latter keeps the centered rectangular symmetry of initial slab slightly compressed along a direction coincided with large sides of elemental rectangles. We have considered two sets of SW TiO2 NTs with optimized six- and twelve-layer structures, which possess chiralities (−n, n) an…
Ultracold Rare-Earth Magnetic Atoms with an Electric Dipole Moment
2018
We propose a new method to produce an electric and magnetic dipolar gas of ultracold dysprosium atoms. The pair of nearly degenerate energy levels of opposite parity, at 17513.33 cm$^{-1}$ with electronic angular momentum $J=10$, and at 17514.50 cm$^{-1}$ with $J=9$, can be mixed with an external electric field, thus inducing an electric dipole moment in the laboratory frame. For field amplitudes relevant to current-day experiments, we predict a magnetic dipole moment up to 13 Bohr magnetons, and an electric dipole moment up to 0.22 Debye, which is similar to the values obtained for alkali-metal diatomics. When a magnetic field is present, we show that the electric dipole moment is strongly…
Probing mechanical quantum coherence with an ultracold-atom meter
2011
We propose a scheme to probe quantum coherence in the state of a nano-cantilever based on its magnetic coupling (mediated by a magnetic tip) with a spinor Bose Einstein condensate (BEC). By mapping the BEC into a rotor, its coupling with the cantilever results in a gyroscopic motion whose properties depend on the state of the cantilever: the dynamics of one of the components of the rotor angular momentum turns out to be strictly related to the presence of quantum coherence in the state of the cantilever. We also suggest a detection scheme relying on Faraday rotation, which produces only a very small back-action on the BEC and it is thus suitable for a continuous detection of the cantilever'…
Experimental verification of position-dependent angular-momentum selection rules for absorption of twisted light by a bound electron
2018
We analyze the multipole excitation of atoms with twisted light, i.e., by a vortex light field that carries orbital angular momentum. A single trapped $^{40}$Ca$^+$ ion serves as a localized and positioned probe of the exciting field. We drive the $S_{1/2} \to D_{5/2}$ transition and observe the relative strengths of different transitions, depending on the ion's transversal position with respect to the center of the vortex light field. On the other hand, transition amplitudes are calculated for a twisted light field in form of a Bessel beam, a Bessel-Gauss and a Gauss-Laguerre mode. Analyzing experimental obtained transition amplitudes we find agreement with the theoretical predictions at a…
Production and detection of atomic hexadecapole at Earth's magnetic field
2007
Anisotropy of atomic states is characterized by population differences and coherences between Zeeman sublevels. It can be efficiently created and probed via resonant interactions with light, the technique which is at the heart of modern atomic clocks and magnetometers. Recently, nonlinear magneto-optical techniques have been developed for selective production and detection of higher polarization moments, hexadecapole and hexacontatetrapole, in the ground states of the alkali atoms. Extension of these techniques into the range of geomagnetic fields is important for practical applications. This is because hexadecapole polarization corresponding to the $\Delta M=4$ Zeeman coherence, with maxim…
Ferromagnetic gyroscopes for tests of fundamental physics
2020
A ferromagnetic gyroscope (FG) is a ferromagnet whose angular momentum is dominated by electron spin polarization and that will precess under the action of an external torque, such as that due to a magnetic field. Here we model and analyze FG dynamics and sensitivity, focusing on practical schemes for experimental realization. In the case of a freely floating FG, we model the transition from dynamics dominated by libration in relatively high externally applied magnetic fields, to those dominated by precession at relatively low applied fields. Measurement of the libration frequency enables in situ measurement of the magnetic field and a technique to reduce the field below the threshold for w…
Extraordinary tuning of a nanocavity by a near-field probe
2011
Abstract We report here an experimental observation of an extraordinary near-field interaction between a local probe and a small-volume solid-state nanocavity. We directly compare the normally observed near-field interaction regime driven by the perturbation theory and then report the extraordinary interaction regime. Subsequently, we show that the cavity can take up to 2 min to recover from this interaction after removing the probe and that leads to an extraordinary blue-shift of the cavity resonance wavelength (∼15 nm) which depends on the probe motion above the cavity and not the position. The reasons for this effect are not fully understood yet but we try to give some explanations.