Method of Direct Detection and Investigation of Long-Lived Excited States of Singly and Multiply Charged Ions of Transition and Rare-Earth Metals

JETP Letters - A method has been proposed for the direct detection and study of long-lived excited states of singly and multiply charged ions of transition and rare earth metals. It allows both the...     

Fluorescence Spectroscopy of Polymer Systems Doped with Rare-Earth Metal Ions and Their Complexes

Abstract

There has been an increased attention to explore the possibility of using polymer materials with rare-earth (RE) metal ions and their complexes as potential optical materials due to their capability of exhibiting novel and unusual properties. The fluorescence characteristics of polymer systems doped with RE metal ions and/or their complexes were analyzed and the effects of the doping metal ion/metal complexes as well as nature of the material were discussed. Electron transitions of REs can be manipulated by efficient ligand designs and proper doping into the polymer matrix. Emphasis was especially focused on the accommodation of the metal ion/metal complex in polymer matrix as well as its role in fluorescence. The photochemistry of the fluorescent polymer matrices with RE complexes is expected to open up frontier fields that lie between photophysics and materials science. Recent developments on a new aspect of these technologies related to the fluorescence dynamics in polymer analysis will also be discussed in this present review.     

Radiationless Energy Transfer Between Rare-Earth Ions in Solutions and its Application to the Investigation of Complexation Processes

Radiationless energy transfer between rare-earth ions (Ln³⁺) in solutions has some features: 1) the electronic transitions in Ln³⁺ complexes causing the luminescence of energy donor and the absorption of energy acceptors are forbidden by Laporte's rule and are weakly intensive. Therefore the critical radius (R_o) of energy transfer between the rare-earth ions for dipole-dipole mechanism is close to that for exchange-resonant mechanism. This fact presents difficulties for unequivocal interpretation of the energy transfer mechanism. 2) The plus-three lanthanide ions exist in solution as a set of complexes with different number of charged ligands in the inner coordination sphere and hence with different total charge of complexes.     

Analysis of the Light-Flavor Scalar and Axial-Vector Diquark States with QCD Sum Rules

In this article, we study the light-flavor scalar and axial-vector diquark states in the vacuum and in the nuclear matter using the QCD sum rules in a systematic way, and make reasonable predictions for their masses in the vacuum and in the nuclear matter.     

Analysis of the Triply Heavy Baryon States with QCD Sum Rules

In this article, we study the (1/2) ± and (3/2)± triply heavy baryon states in a systematic way by subtracting the contributions from the corresponding (1/2)■ and (3/2)■ triply heavy baryon states with the QCD sum rules, and make reasonable predictions for their masses.     

Properties of Superposit ion of Displaced Number States and Their Interaction with Two-Level Atoms

We obtain the compact form of matrix elements of displacement operator between number states which is convenient for numerical computations by invoking the generalized Hypergeometric functions. The nonclassical properties of superposition of displaced number states and generation of them in Kerr medium are studied in detail. The evolution of atomic population inversion in the intensity-dependent Jaynes-Cummings model with the present superposition states as its input is also investigated.     

Capture and Dissociative Capture of a Single Electron in the Process of Interaction of Doubly Charged Ions with CO Molecules

Technical Physics - The absolute cross sections of single-electron capture and single-electron capture with dissociation in the interaction between incident He2+, C2+, N2+, and O2+ ions with...     

The Effect of Ammonia Ions on the Absorption and Fluorescence of an Oxazine Dye

The addition of ammonium hydroxide to a weakly acidic oxazine perchlorate dye produces a color change by means of a deprotonation mechanism in which the hydroxyl radical abstracts a loosely bound proton, leaving the positively charged ammonium cation to counter balance the perchlorate anion. This reaction produces significant absorption and fluorescence band shifts which can be accounted for by a semi-classical oscillator model predicting two dichroic electronic band systems associated with this dye. Peculiar wavelength excitation dependent fluorescence band shifts are attributed to overlapping triplet states simultaneously excited.     

Generation of Superpositions of Two-Mode Coherent States for the Motion of Two Trapped Ions

We propose a method for the generation of superpositions of two-mode coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are driven by a single travelling-wave laser field tuned to the carrier. Then a measurement of the internal states collapses the vibrational modes to the entangled coherent state.     

Generation of Superpositions of Two-Mode Coherent States for the Motion of Two Trapped Ions

We propose a method for the generation of superpositions of two-mode coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are driven by a single travelling-wave laser field tuned to the carrier. Then a measurement of the internal states collapses the vibrational modes to the entangled coherent state.     

Time-Resolved Vacuum Ultraviolet Spectroscopy of Er<Superscript>3+</Superscript> Ions in the SrF<Subscript>2</Subscript> Crystal

The photoluminescence and photoexcitation spectra as well as the luminescence decay kinetics of Er³⁺ ions in the visible ultraviolet and vacuum ultraviolet (VUV) regions have been studied by the method of low-temperature, time-resolved VUV-spectroscopy on excitation by synchrotron radiation. In the VUV spectral region of the luminescence of SrF₂:1% Er³⁺, the 146.5-nm band with a time of decay of less than 0.6 nsec was revealed together with the well-known emission band at 164.3 nm (decay constant in the microsecond range). Its possible nature is discussed. The specific features of the formation of photoexcitation spectra of the f-f and f-d transitions in the Er³⁺ ion are considered. Competition between the processes of excitation of f-f and d-f luminescence has been revealed. It manifests itself in the inverse relationship of their photoexcitation spectra in a range of energies of incident photons that are close to the position of the 4fⁿ⁻¹5d configuration levels. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 519–523, July–August, 2005.     

Bell态原子与双模纠缠相干光场相互作用系统的原子布居数演化

运用全量子理论并结合数值计算方法,研究了处于Bell态的两个全同二能级纠缠原子与双模纠缠相干光场相互作用系统的原子布居数演化特性.讨论了双原子体系的初态、光场的平均光子数、双模纠缠相干光场的纠缠程度以及双原子体系的原子间耦合强度对原子布居时间演化的影响.结果表明:双原子体系的初态为|β11〉时,原子布居数不随时间变化;初态为|β00〉、|β01〉和|β10〉时,当初始平均光子数增大到一定数值时演化特性呈现出周期性的崩塌和回复效应,随初始光子数的增加时间演化曲线的振荡频率增大振幅减小,且初态为|β00〉或|β10〉时原子布居的回复周期是初态为时|β01〉的两倍;双模纠缠相干光场的纠缠程度以及原子间偶极相互作用的强弱对Rabi振荡频率没有影响但对振幅有着显著的影响.     

The Calculations of the Concentrations,of the Radial Distributions,and of the Radial Particle Currents of Excited and of Doubly Charged Ions in Low Pressure Discharges

A system of differential equations describing the radial profiles of the number densities and of the radial drift velocities of the ions and of the electrons in positive columns at low pressure containing several species of ions is derived. Excited ions and doubly charged ions, generated in two-step processes by electron impacts, the inertia of the ions and space charge effects are taken into account. For the excited ions de-excitation processes by electron collisions and by spontaneous emission are regarded. A set of nonlinear equations to determine the population densities and the initial values of the differential equations and corresponding boundary conditions are put up. Numerical solutions are given for discharges in argon under free-fall conditions similiar to argon ion lasers. One notices that without stepwise processes via excited ion levels the concentration of double charged ions remains small. In some cases the radial drift of the ions considerably reduces the population of the metastable ion levels. The radial density profiles of the double charged ions and of long-living excited ions considerably deviate from the squared radial profile of the electron density. In addition, for low degrees of ionization the theory of the free-fall column given by Tonks and Langmuir is extended to plasmas containing two species of ions.     

克尔介质中双模纠缠相干光与贝尔态原子相互作用系统的光子统计特性

运用全量子理论并结合数值计算方法,研究了克尔介质腔中处于贝尔态的两个全同二能级纠缠原子与双模纠缠相干光场相互作用系统的光子统计特性。讨论了双原子体系的初态、初始光场的平均光子数、双模纠缠相干光场的纠缠程度以及克尔介质与双模光场的耦合强度对光子统计特性的影响。结果表明:忽略克尔介质的作用时,只有当双原子体系的初态为0β1〉或1β1〉时,在一定的条件下才可出现光子的反聚束效应,而当双原子体系的初态为β00〉、1β0〉时,光场在其演化过程中不出现光子的反聚束效应。而当考虑克尔介质的作用时,四种初态下光场演化过程中均有可能出现光子的反聚束效应。光子的反聚束效应出现的次数、时间和深度极其敏感地依赖于初始光场的平均光子数和克尔介质与双模光场的耦合强度,同时也受到双模纠缠光场的纠缠程度的影响。     

Doubly‐Charged Xe Ions Evidenced by Time Resolved RPA Measurement in the Far Field Plume of a Low‐Power HET

A low power Hall Effect Thruster (HET), based on a permanent magnet circuit, was investigated in the GREMI laboratory facility. The thruster operated in the working range between 50 and 300 W and the previously measured thrust is between 4 and 16 mN for an anodic efficiency respectively between 15% and 27%. The pulsed character of the thruster current is an important feature of this HET. The ion current's bursts are recorded at 30 and 70 cm from the exit plane in the thruster plume and are time‐resolved, which lead to a preliminary analysis of the time of flight (TOF) phenomena. This paper presents a detailed study of these bursts of ion current in the plume. The total ion current is shown to be a superposition of 2 distinct contributions of charged species. In complement, a controlled single current interruption in stable anodic current condition leads to exactly the same features than in oscillating mode. This crucial verification garantees the validity of the time of flight origine of the two distinct contributions. Then, the slower one is the more intense and is proportional to the ion Xe+ current whereas the faster one could be attributed either to doubly‐charged Xe⁺⁺ or to superfast Xe⁺. The work presents a way to determine unambiguously the nature of the fast contribution by recording the Retardated Potential Analyser (RPA) signals at various repelling grid potentials with respect to time. The energy distribution of the 2 wellseparated contributions are reconstructed and confirms the contribution of doubly‐charged xenon ions (Xe⁺⁺) in the plume. This way of RPA collecting data and interpretation presents the main advantage tobe an easy way for the identification of the nature of the charged species in the plume. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Production of Charged Heavy Quarkonium-Like States at the LHC and Tevatron

We study prompt hadroproduction of the charged bottomonium-like states Zb± （10610） and Zb±（10650）, and the charged eharmonium-like states Zc± （3900） and Zc± （4020）, at the Tevatron and the LHC, provided that these states are S-wave hadronic molecules. Using two Monte Carlo event generators, Herwig and Pythia, to simulate the production of heavy meson pairs, we derive an order-of-magnitude estimate of the production rates for these four particles. Our estimates yield a cross section at the nb level for the Zb（10610） and Zb（10650）. The results for the Zc（3900） and Zc （4020） are larger by a factor of 2~30. These cross sections are large enough to be observed, and measurements at hadron colliders in the future will supplement the study using electron-positron collisions, and therefore allow to explore the mysterious nature of these exotic states.     

The Excitation Temperatures of Nonmetal Atoms and the OH Temperatures in Microwave-Induced Plasma

Abstract

The excitation temperatures of nonmetal atoms and the OH molecule temperatures have been measured in argon MIP, operating under atmospheric pressure at different experimental conditions. Atoms of Ar I, P I and H have been used as thermometric species. The rotational and vibrational temperatures have been obtained from the OH A²Σ⁺ - X²? band spectra. The ^SR₂₁ ratational lines have been used for the first time for the temperature measurements. The energy distributions observed here are discussed.     

Na原子及类Na离子Fe15+价壳层光电离过程的理论研究

采用相对论多组态Dirac-Fock理论,计算了Na原子及类Na离子Fe15++基态的光电离截面.对Na原子,考虑相对论效应与弛豫效应,本文计算结果与前人计算结果和实验测量结果一致性较好.对Fe15+离子的最外价电子,相对论效应对其光电离过程产生主要影响,而轨道弛豫效应则可忽略不计;对中性Na原子则情况完全不同:轨道弛豫效应的影响非常显著,但其光电离截面对相对论效应仅有非常微弱的依赖.