Effect of the Tensor Force on Charge-Exchange Spin-Dependent Multipole Excitations

The charge-exchange spin-dipole （SD） and spin-quadrupole （SQ） strength functions of 90Zr are calculated with and without the tensor terms of the Skyrme interaction in self-consistent HF＋RPA approach. It is found that, in SD and SQ transitions, the RPA correlations associated with the tensor terms shin dramatically the strengths of （Ylσ）λ = l？1 and （Ylσ）λ = 1 modes upward and downward, respectively, and also shift the strengths of （Ylσ）λ = l ＋ 1 modes upward. The coupling between （Yl = λ ？ 1σ）λ and （Yl = λ ＋ 1σ）λ modes arising from the tensor correlation is noticeable. The RPA tensor correlations produce strengths of SD and SQ modes, which are distributed in a much wider energy range, and the （Ylσ）λ = l ？ 1 modes dominate the high energy part of the strength functions. These energy shifts and coupling effects of different modes can be understood qualitatively by expressing a finite range tensor force in a separable form.     

Multi-Electron Processes in 4.15-11.08 keV/u^13C^6＋ on Argon Collisions

The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the constants of 0.514-0.05, 0.204-0.03, 0.064-0.03 and 0.024-0.01 in this region. The significance of the multi-electron process in highly charged ions （HCIs） with argon collisions is demonstrated （σ^ME/σ^SC as high as 0.794-0.06）. In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model （MCBM）, the extended classical over-the-barrier model （ECBM） and the semiempirical scaling laws （SL）. The result is compared with these classical models and with our previous work of ^13C^6＋ -Ne collisions [Chin. Phys. Lett. 23 （2006） 95].     

Kr L X-ray and Au M X-ray emission for 1.5 MeV–3.9 MeV Kr~(13+) ions impacting on an Au target

Kr L X-ray and Au M X-ray emission for Kr13＋ ions with energies of 1.5 MeV and 3.9 MeV impacting on an Au target are investigated at heavy ion research facility in Lanzhou （HIRFL）. The L-shell X-ray yield per ion of Kr is measured as a function of incident energy. In addition, Kr L X-ray production cross section is extracted from the yield and compared with the result obtained from the classical binary-encounter approximation （BEA） model. Furthermore, the intensity ratio of the Au M/33 to Ma1 X-ray is investigated as a function of incident energy.     

Transfer Ionization of Helium in Collisions with C^q＋ and O^q＋ （q =1 - 3）

Cross-section ratios σTI/σSC of transfer ionization （TI） to single capture （SC） of C^q＋- and O^q＋-He （q = 1 - 3） collisions in the energy range of 15-440 keV/u （0.8-4.2 vBohr） are experimentally determined. It is shown that σTI/σSC strongly depends on the projectile velocity, and there is a maximum for E（keV/u）/q1/2 ≈, 150. Combining the Bohr-Lindhard model and the statistical model, a theoretical estimate is presented, in reasonable agreement with the experimental data when E（keV//u）/q^1/2 〉 35.     

L-Shell X-Ray Production Cross Sections of Au and Ir Atoms by Electron Impact near the Threshold Region

L-shell production cross sections Lα, Lβ and Lγ for Au and Ir atoms have been measured by electron impact at incident electron energies of about one to three times of the threshold energy. The total production cross section and mean ionization cross section were obtained from the experimental results and by using mean fluorescence yield, respectively. The influence of electrons reflected from the substrate and multiple electron scattering inside the target have been corrected. The experimental results are compared with the existing measured results and the theoretical predictions.     

Theoretical Study on Negative Parity States of^（191,193,195,197） Au in Particle Triaxial-Rotor Model

By taking the particle triaxial-rotor model with variable moment of inertia, we investigate the energy spectra, the deformation and the single particle configuration of the negative-parity states in nuclei^（191,193,194,197） Au systemically. The calculated energy spectra agree well with experimental data. The obtained results indicate that the negative-parity states in^（191,193,195,197）Au originate from the proton-hole h11/2 configuration coupled to a triaxial oblate Hg core. Meanwhile the main single particle configuration of the bands 1, 2 and 3 are identified to be [5h11/2 1/2） （α=-1/2）, [5h11/2 1/2） （α = 1/2） and 15h9/2 7/2）, respectively.     

X-ray emission from 424-MeV/u C ions impacting on selected target

The K-shell x-rays of Ti, V, Fe, Co, Ni, Cu, and Zn induced by 424-MeV/u C~(6+) ion impact are measured. It is found that the K x-ray shifts to the high energy side and the intensity ratio of Kβ/Kα is larger than the atomic data, owing to the L-shell multiple-ionization. The x-ray production cross sections are deduced from the experimental counts and compared with the binary encounter approximation(BEA), plane wave approximation(PWBA) and energy-loss Coulomb-repulsion perturbed-stationary-state relativistic(ECPSSR) theoretical predictions. The BEA model with considering the multipleionization fluorescence yield is in better consistence with the experimental results. In addition, the cross section as a function of target atomic K-shell binding energy is presented.     

Multi-Electron Processes in ^13C^6＋ Ions with Neon Collisions in Energy Region 4.15-11.08 keV/u

The cross-section ratios of double-, triple-, quadruple-, and the total multi-electron processes to the single electron capture process （σ^DE/σ^SC, σ^TE/σ^SC, σ^QE/σ^SC and σ^ME/σ^SC） as well as the relative ratios among reaction channels in double-electron active, triple-electron active and quadruple-electron active are measured in ^13C^6＋_Ne collision in the energy region of 4.15-11.08keV/u by employing position-sensitive and time-of-flight coincident techniques. It is determined that the cross-section ratios σ^DE /σ^SC, σ^TE /σ^SC, σ^QE /σ^SC and σ^ME /σ^SC are approximately the constants of 0.20 ± 0.03, 0.16 ± 0.04, 0.06 ± 0.02 and 0.42 ± 0.05. These values are obviously smaller than the predictions of the molecular Coulomb over-the-barrier model （MCBM） [J. Phys. B 23 （1990） 4293], the extended classical over-the-barrier model （ECBM） [J. Phys. B 19 （1986） 2925] and the semiempirical scaling laws （SL） [Phys. Rev. A 54 （1996） 4127]. However, the relative ratios among partial processes of DE, TE and QE are found to depend on collision energy, which suggests that the collision dynamics depends on the collision velocity. The limitation of velocity-independent character of ECBM, MCBM and SL is undoubtedly shown.     

Improved photoluminescence behavior of Eu3＋-activated Ca5（PO4）3F red nanophosphor by adding Li＋, Au3＋, and Bi3＋ as co-dopants

A series of Ca499（PO4）3F：1%Eu^3＋, 1%X （X = Li＋, Au3＋, and Bi3＋） nanoparticles are prepared using hydrothermal method, with an average size of 33-62 nm. We study the improved photoluminescence properties of Ca4.99（PO4）3F：1%Eu3＋ by co-doping with Li＋, Au3＋, and Bi3＋ ions, respectively, and the enhancement of the emission intensities of Eu3＋ is observed in these samples. The effects of Li＋ acting as a charge compensator, Au3＋ as a plasma surface sensitizer, and Bi3＋ as an energy conversion agent are discussed. The results show Ca4.99（PO4）3F：1%Eu3＋, 1%X nanoparticles are a promising candidate as a red component for near-ultraviolet light-emitting diodes.     

Determination of the nucleon-nucleon interaction in the ImQMD model by nuclear reactions at the Fermi energy region

The nucleon-nucleon interaction is investigated by using the improved quantum molecular dynamic （ImQMD） model with three sets of parameters IQ1, IQ2 and IQ3, in which the corresponding incompressibility coefficients of nuclear matter are different. The charge distributions of fragments are calculated for various reaction systems at different incident energies. The parameters strongly affect the charge distributions and the fragment multiplicity spectrum below the threshold energy of nuclear multifragmentation. The fragment multiplicity spectrum for 238U＋197Au at 15 A MeV and the charge distributions for 129Xe＋12~Sn at 32 and 45 A MeV, and 197Au＋197Au at 35 A MeV are reproduced by the ImQMD model with the set of parameter IQ3. It is found that： 1） The charge distribution of the fragments and the fragment multiplicity spectrum are good observables for testing the model and the parameters. 2） The Fermi energy region is a sensitive energy region for studying nucleon-nucleon interaction.     

Bounce-averaged Pitch-angle Diffusion by Electromagnetic Ion Cyclotron Waves in Multi-ion Plasmas

We present a study on the gyroresonant interaction particles in multi-ion （H^＋, He^＋, and O^＋） plasmas between electromagnetic ion cyclotron waves and ring current We provide a first evaluation of the bounce-averaged pitch angle diffusion coefficient 〈Dαα〉 for three typical energies of 50, 100 and 150keV at L ≈ 3.5, the heart of the symmetrical ring current. We show that in the H^＋-band and He^＋-band, 〈Dαα〉 can approach - 10^-4 s^-1 for ion H^＋, and - 5 × 10^-5 s^-1 /or ion He^＋; meanwhile, in the O^＋-band, 〈Dαα〉 can reach - 10^-5 s^-1 for ions He^＋ and O^＋. The results above show that the EMIC wave can efficiently produce precipitation loss of energetic （- 100 keV） ions （H^＋, He^＋ and even O^＋）, and such a wave tends to be a serious candidate responsible for the ring current decay.     

Stereodynamics of the reactions Ne＋H＋/Ne＋D2＋/Ne＋W2

The vector correlations between products and reagents for the reactions Ne＋H2＋, Ne＋D2＋, and Ne＋T2＋ are calculated by means of the quasi-classical trajectory method on a new potential energy surface constructed by Lfi et al, [J. Chem. Phys. 2010 132, 014303]. The polarization-dependent differential cross-sections （27π/σ）（dσ00/dωt）, （2π/σ）（dσ20/dwt）, （27π/σ）（dσ22＋/dwt）, and （2π/σ）（dσ21-/dwt）, and the distributions of P（θr）, P（φ）, and P（θr, Cr） are calculated. The isotopic effect, which is associated with the difference in mass factor among the three reactions, is revealed.     

Super energy flows in a waveguide filled with air and left-handed materials

The phenomena of super energy flows are studied theoretically and numerically in a parallel-plate waveguide which is filled with two layered equally-thick different media, i.e. air and specific left-handed materials （LHM） with εr1 = -1/（1 ＋δ） ＋iγ and μr1 = -（1 ＋ δ） ＋ iγ. In this special waveguide, two-directional super-energy flows are excited by a three-dimensional horizontal electric dipole at the same time, which has transmission patterns different from those of two-dimensional source and three-dimensional vertical electric dipole. We also show that the retardation and loss in LHM are sensitive to the amplitude of super power densities, and the dimensions of waveguide determine the propagating modes, which makes super energy flows more practical.     

Simulation of energy scan of pion interferometry in central Au＋Au collisions at relativistic energies

We present a systematic analysis of two-pion interferometry for the central Au＋Au collisions at √SNN=3, 5, 7, 11, 17, 27, 39, 62, 130 and 200 GeV/c with the help of a multiphase transport （AMPT） model. Emission source-size radius parameters Rlong, Rout, Rside and the chaotic parameter A are extracted and compared with the experimental data. Transverse momentum and azimuthal angle dependencies of the HBT radii are also discussed for central Au＋Au collisions at 200 GeV/c. The results show that the HBT radii in central collisions do not change much above 7 GeV/c. For central collisions at 200 GeV/c, the radii decrease with the increasing of transverse momentum PT but are not sensitive to the azimuthal angle. These results provide a theoretical reference for the energy scan program of the RHIC-STAR experiment.     

Characterization and application in XRF of HfO_2-coated glass monocapillary based on atomic layer deposition

Coating a glass monocapillary x-ray optics with high-density film is a promising way to improve transmission characteristics. For a long time, it has been a challenge to coat a high-density film in the inside of monocapillary with an extremely high length-to-diameter ratio. In this work, Hf O2 film is deposited on the inner wall of a tapered glass monocapillary with length 9.9 cm, entrance diameter 596.4 μm, and exit diameter 402.3 μm by atomic layer deposition. The coated and uncoated monocapillaries are studied by the transmission process of x-rays with energy from 5 ke V to 100 ke V and the x-ray fluorescence(XRF) spectra of a Mo sample are detected. Improved transmission characteristics have been obtained for the Hf O_2-coated monocapillary. The energy upper limit of focused x-rays increases from 18.1 ke V to 33.0 ke V and the ‘penetration halo' is suppressed to some extent. The XRF spectrum presents two stronger peaks at ～ 17.4 ke V and～ 19.6 ke V which are considered as the characteristic x-rays of Mo K_α and Mo K_β. These results reveal that more higher energy x-rays from the W x-ray tube are totally reflected on the inner wall of the Hf O_2-coated glass monocapillary due to the increase of total reflection critical angle. This work is significant for more applications of monocapillary in higher energy x-ray field.     

Decay pathways of superexcited states of nitrous oxide

The ionization and ionic dissociation of the superexcited state of N20 are studied by using electron energy loss spectroscopy and positive ion time-of-flight mass spectroscopy at different momentum transfers; that is, 0 and 0.23 a.u. （atomic unit） . The transitions at 13.8 eV and 14.0 eV are reassigned as 3pπ（000） and 3pσ（000） converging to A^2∑＋, respectively. The competition between the main decay pathways of superexcited states at different momentum transfers is revealed. It is found that 3dσ converging to C^2∑＋ mainly decays into N2O^＋ while 4dσ can decay into both N2^O＋ and NO^＋.     

Extended Measurement of the v2 (1- ←0+) Band of H3O+ by Mid-Infrared Diode Laser Spectroscopy

Twenty-five new R-branch lines of the v2（1^-← 0^＋） band of H3O^＋ are measured using diode laser velocity modulation spectroscopy between 1070 and 1230 cm^-1. The H3O^＋ ions are produced in a high voltage ac discharge with water diluted in helium. The observed lines together with all the previously published measurements are fit to the standard vibration-rotational Hamiltonian of an oblate symmetric top, yielding a set of improved molecular constants. All the sextic centrifugal distortion constants for both 0^＋ and 1^- states are determined precisely. The observed R（13, 0） transition is shifted about -0.129 cm^-1 from its calculated value, indicating that a near degeneracy exists between the （13, 0）^＋ and （13, 3）^- ground-state rotation-inversion levels.     

Secondary X-Ray Environment in the Lower Atmosphere of the Earth during Monsoon Season over Udaipur City （India） in July-September 2006

We present a study on the secondary x-rays of energy band 2-100 keV emitted by the intruded principal pollutant components （gases and minerals） brought up in the lower atmosphere by dust storms, monsoon drift and the gravitational pull on meteoritic showers. On the ground we employed a 1.5 × 1 inch^2 NaI crystal in a scintillation detector, suitable for the energy range 2-100 keV of secondary x-rays, providing better energy resolution than a larger sized crystal. In order to eliminate the radioactive background of the Earth, the detector was well shielded on all sides with the help of the lead （Pb） container, except with a.small open window at the top to permit only vertically incident secondary radiation. The results from the data analysis obtained during the monsoon over Udaipur city （India） during the period from July to September （2006） have revealed a linear correlation between dust storm cure monsoon clouds and observed luminosities of secondary x-ray radiation from intruded pollutants. We found intense flux of secondary x-rays from the intruded pollutants when heavy dust and monsoon clouds were brought up by dust storms and monsoon drift in the lower atmosphere over Udaipur city as compared to normal days. Thus, secondary x-rays in the environment provide a tool for investigation of local intrusive pollutant components in the lower atmosphere.     

Laser Phase Relations of High-Order Harmonic Generation

Laser phase relations of high-order harmonic generation （HHG） are calculated with the saddle point theory. The results show a two-peak structure including a symmetric and an asymmetric temporal distributions of the instantaneous frequency of HHG radiation. These distributions are fitted with Gaussian and polynomial functions, respectively. Two calculation formulae are presented to analyse attosecond x-rays with specified time duration and energy bandwidth in experiments.