International Journal of Modern Physics B

This paper gives a survey of physical phenomena manifesting themselves in electron and photon collisions with atomic clusters. The emphasis is made on electron scattering, photoabsorption and photoionization of fullerenes and metal clusters, however some results are applicable to other types of clusters as well. It is demonstrated that the diffraction and interference phenomena play an important role in the processes of clusters interaction with photons and electrons. The essential role of the multipole surface and volume plasmon excitations is elucidated in the formation of electron energy loss spectra on clusters as well as in the total inelastic scattering cross sections and in multiphoton absorption regime. Attention is paid to the elucidation of the role of the polarization interaction in low energy electron-cluster collisions. This problem is considered for the electron attachment to metallic clusters and the plasmon enhanced photon emission. The mechanisms of electron excitation widths formation and the relaxation of electron excitations in metal clusters and fullerenes are discussed.

We have analyzed the rotating effect of an Ar⁺ linearly polarized laser beam on a dye-doped nematic liquid crystal (DDNLC) in a pump-probe experiment. An asymmetric capillary cell with two polymer coated glasses was used. An easy axis was induced by rubbing one surface, the other one remained non-oriented. The exciting laser beam entering the orienting surface has the polarization direction perpendicular to the easy axis. The time dependent transmitted intensity of a probe He–Ne laser beam (polarization direction parallel to the easy axis) has been measured. For large enough Ar⁺ laser power a non-monotonous curve (having one or even two maxima) has been observed. We develop a model which explains our experimental data by taking into account the gliding of the easy axis on the orienting surface. The azimuthal anchoring gliding angle has been estimated.

The two dimensional stochastic time model of scrape-off layer (SOL) turbulent transport is studied. The instability arisen in the system with respect to the stochastic perturbations of both either density or vorticity reveals itself in the strong outward bursts of particle density propagating ballistically across the SOL. The stability and possible stabilization of the cross-field turbulent system depend very much upon the reciprocal correlation time between density and vorticity fluctuations. The probability distribution function (pdf) of the particle flux for the large magnitudes of flux events can be modeled with a simple discrete time toy model of random walks concluding at a boundary. The spectra of wandering times feature the pdf of particle flux in the model and qualitatively reproduce the experimental statistics of transport events.

We present exact solutions of the one-dimensional Schrödinger equation with a harmonic oscillator plus an inverse square potential. The ladder operators are constructed by the factorization method. We find that these operators satisfy the commutation relations of the generators of the dynamical group SU(1, 1). Based on those ladder operators, we obtain the analytical expressions of matrix elements for some related functions ρ and with ρ=x². Finally, we make some comments on the Barut–Girardello coherent states and the hidden symmetry between E(x) and E(ix) by substituting x→ix.

The equilibrium properties of the Blume–Emery–Griffiths (BEG) model Hamiltonian with the arbitrary bilinear (J), biquadratic (K) and crystal field interaction (D) are studied using the genetic algorithm technique. Results are compared with lowest approximation of the cluster variation method (CVM), which is identical to the mean field approximation. We found the genetic algorithm to be very efficient for fast search at the average fraction of the spins, especially in the early stages as the system is far from the equilibrium state. A combination of the genetic algorithm followed by one of the well-tested simulation techniques seems to be an optimal approach. The curvature of the inverse magnetic susceptibility is also presented for the stable state of the BEG model.

In this paper, two definitions about traffic congestion are proposed. We describe the traffic congestion spreading with the SEIR model of a complex small-world network. In addition, the relationships among the congestion factor, the number of average infection, the average recover rate and the infection rate are given by simulations in general traffic congestion conditions.

ZnO nano wire synthesized by microemulsion mediated hydrothermal process is characterized by X-ray diffraction, scanning electron microscope, UV–VIS and photoluminescence. The optical and thermal properties are then studied by photoacoustics. These studies reveal that the ZnO nano wires exhibit a strong ultra violet absorption and a relatively weak defect emission.

We numerically study the thermodynamic properties of two Archimedean lattices¹ with Ising spins using Wang–Landau algorithm of the Monte Carlo simulation. The two Archimedean lattices are of the type (3, 12²) and Kagomé, for which we are particularly interested in the frustration effects. The internal energy, specific heat, free energy, entropy, magnetization and spin susceptibility are calculated.