Dirac Optical Potential of p-^14Be and Pronounced “Long-Tail” Shape

The Dirac optical potential for p-^14 Be elastic scattering is evaluated by the relativistic impulse approximation. Each of the real part and the imaginary part of the potential shows a pronounced “long tail” for the proton elastic scattering from halo nucleus ^14Be compared with the potentials for proton scattering from its adjacent nuclei ^12C and ^16O, which do not have halo structures.This kind of “long tail” phenomenon suggests another signature for halo nuclei.     

Supersymmetry and Shape Invariance of Hartmann Potential and Ring-Shaped Oscillator Potential in the γ and θ Dimensions of Spherical Polar Coordinates

This article shows that in spherical polar coordinates, some noncentral separable potentials have super-symmetry and shape invariance in the r and θ dimensions, we choose Hartmann potential and ring-shaped oscillator astwo important examples, thus in principle the energy eigenvalues and energy eigenfunctions of such the potentials in ther and θ dimensions can be obtained by the method of supersymmetric quantum mechanics. Here we use an alternativemethod to get the required results.     

Optical Potential Calculations of Positron-H2 Elastic Collision

We report the calculations of the elastic scattering differential cross section for positron H2 collisions with the impact energy below the positronium formation threshold. Our calculation is based on the static-exchange-optical model which has obtained great success in the case of electron scattering. The effective potential used here includes the static and optical potentials. The optical method can completely include the second-order effect arising from real and virtual excitation of target states, which is important for the scattering. A comparison is made with the available theoretical calculations.     

Exact Bound Solution of the Klein-Gordon Equation and the Dirac Equation with Rosen-MorseⅡ Potential

In this paper, the relativistic Rosen-Morse II potential is investigated by solving the Klein-Gordon and the Dirac equations with equal attractive scalar s(r) and repulsive vector v(r) potentials. The exact energy equations of the bound state are obtained by the method of supersymmetric and shape invariance. Finally, a kind of special potential about Rosen-MorseⅡ potential is discussed.     

Radiative lifetimes of Rydberg states of BeⅠ and BeⅢ

By using the multichannel quantum defect theory(MQDT),we have evaluated the energy levels and lifetimes of 2sns ^3 S1,2snd ^3D(n=3-25)of BeI and 1 sns ^3s1,1snd ^3D(n=3-25)of BeⅢ,These energies and lifetimes that we have calculated not only agree with the recent measurements and theoretical calculation of Ref.4 and Ref.3, but also predict the lifetimes of 66 other highly excited states.     

On the “Equivalence” of the Maxwell and Dirac Equations

It is shown that Maxwell's equation cannot be put into a spinor form that is equivalent to Dirac's equation. First of all, the spinor in the representation of the electromagnetic field bivector depends on only three independent complex components whereas the Dirac spinor depends on four. Second, Dirac's equation implies a complex structure specific to spin 1/2 particles that has no counterpart in Maxwell's equation. This complex structure makes fermions essentially different from bosons and therefore insures that there is no physically meaningful way to transform Maxwell's and Dirac's equations into each other.     

Optical Potential Calculations of Elastic Collision for Electron Scattering by H2

Differential cross sections for the elastic scattering of the electrons by H2 at 100 and 150 e V have been calculatedand compared with experiments. We use the momentum space method in which the electron-molecule system hasa single centre and the effect of higher reaction channels on electron-molecule elastic scattering is approximatedby an ab initio equivalent-local potential. It is added to the exact static-exchange potential for e-H2 scattering.     

Linear and Nonlinear Optical Properties of Quasicrystals

An investigation is carried out on the linear and nonlinear optical properties of quasicrystaJs. The linear and nonlinear susceptibilities are determined for two- and three-dimensional ctuasicrystals. The results show that for optical linearity, two-dimensional quasicrystals are uniaxial, while icosahedral quasicrystals are optically isotropic. Meanwhile all ctuasicrystals, except those with 5, 5m, N, Nmm (N = 8, 10, 12) symmetries, have no the firstorder optical nonlinearity. The tensor scheme of the first order nonlinear susceptibility is the same for these eight exceptional kinds of quasicrystals.     

Effect of the Taper Shape upon Transmission Efficiency of Fiber Probes for Scanning Near-field Optical Microscopy

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Synthesis and Optical Properties of ZnO Nanostructures

ZnO nanostructures with different morphologies were fabricated by changing the partial oxygen pressure. The structures, morphologies and optical properties of ZnO nanostructures were investigated by x-ray diffraction, field emission scanning electron microscopy and photoluminescence (PL) spectra at room temperature. All the samples show preferred orientation along the c-axis. The oxygen partial pressure and the annealing atmosphere have important effect on the PL property of ZnO nanostructures. The high oxygen partial pressure during growth of samples and high-temperature annealing of the ZnO samples in oxygen can increase oxygen vacancies and can especially increase antisite oxygen (OZn) defects, which degraded the near band-edge emission. However, the annealing in 1-12 can significantly modify the NBE emission.     

Effective Mass and Pseudoscalar Interaction in the Dirac Equation with Woods–Saxon Potential

We consider the one-dimensional Dirac equation with the Woods–Saxon potential in the Framework of position dependent mass and pseudoscalar interaction. By imposing appropriate constraints on the mass function and the pseudoscalar term new exact solvable models are obtained. A detailed study of the scattering and bound-states problems for these models is presented. Meanwhile, we work out the exact expressions for the transmission and reflection probabilities of scattered states and obtain the exact equation for the energy eigenvalues associated to bound states. In particular, transmission resonance at zero-momentum is observed for supercritical states.     

Measurement of Change of ^7Be Decay Rate in Be and Au

We have measured the possible change of the decay rate of ^7Be implanted into hosts of natural beryllium and natural gold. No difference between the ^7 Be decay rates in the two hosts is observed within the experimental precision of 0.12%. This result implies that change of the decay rate of ^7Be implanted in different materials cannot be simply expected from the electron affinity difference consideration lonely and the lattice structure of the host materials should be taken into account.     

Potential energy curves and spectroscopic properties of X2∑ and A2П states of 13C14N

The potential energy curves(PECs) of X2+Σand A2Π states of the CN molecule have been calculated with the multireference configuration interaction method and the aug-cc-pwCV5Z basis set. Based on the PECs, all of the vibrational and rotational levels of the13C14N molecule are obtained by solving the Schro¨dinger equation of the molecular nuclear motion.The spectroscopic parameters are determined by fitting the Dunham coefficients with the levels. Both the levels and the spectroscopic parameters are in good qualitative agreement with the experimental data available. The analytical potential energy functions are also deduced from the calculated PECs. The present results can provide a helpful reference for future spectroscopy experiments or dynamical calculations of the molecule.     

Proton Elastic Scattering from ^14Be and Halo Effects

The elastic scattering of p-^14Be system at Elab = 200 MeV is evaluated within the relativistic impulse approximation. We discuss the effects of the halo neutrons on the three observables of the elastic scattering system, such as differential cross section dσ/ dΩ, analyzing power Ay and spin rotation Q. The results of the three observables of the elastic scattering of p-^14Be system are compared with those of p-^12C and p-^16O systems at the same energy as E1ab = 200 MeV. We have found that in the small angular region the Ay and Q, as well as dσ/dΩ, are quite sensitive to the nucleon density distributions on the surface of the target nucleus and offer some unique behaviors of halo nuclei.     

Supersymmetric Content of the Dirac and Duffin-Kemmer-Petiau Equations

We study subsolutions of the Dirac and Duffin-Kemmer-Petiau equations described in our earlier papers. It is shown that subsolutions of the Duffin-Kemmer-Petiau equations and those of the Dirac equation obey the same Dirac equation with some built-in projection operator. This covariant equation can be referred to as supersymmetric since it has bosonic as well as fermionic degrees of freedom.     

Solution of the Dirac Equation with Position-Dependent Mass for q-Parameter Modified P?schl–Teller and Coulomb-like Tensor Potential

In this research, we have been obtained the Dirac equation for q-parameter modified P?schl–Teller potential including a Coulomb-like tensor interaction with arbitrary spin-orbit coupling quantum number by choosing a position-dependent mass. The energy eigenvalues equation and the corresponding unnormalized wave functions have been obtained. The Nikiforov-Uvarov method has been used in the calculations.     

Linear and Nonlinear Optical Characterization of PolyDCHD-HS Films

Waveguiding films of the highly soluble polycarbazolydiacetylene polyDCHD-HS were prepared by spin coating and characterized at different wavelengths: 5 dB/cm propagation losses were observed at 1321 nm.Measurements of the third order nonliearity at 1064nm with the surface plasmon resonance method gave the valueχ(3)= i4.4×10-17+3.5×10-18 m2/V2.     

Properties and Stability of Nanosecond Optical Limiting of Gold Nanoclusters

Optical limitation(OL) performances of the gold nanoclusters protected by C60-tpy have been investigated with 8 ns pulses at 532nm.The experimental results show that the nanocomposite possesses OL effects superior to C60 in toluene.The main mechanism of OL is attributed to the nonlinear absorption and subsequently induced nonlinear scattering during excitation of the pulse.Ageing of the nanocomposite chloroform solution in air lowers the OL performances by a factor of 2.4,which can be due to the formation of aggregates of large gold particles.