Semiclassical scattering on conical intersections

We apply a semiclassical approach to the scattering problem of a vibrational wave packet in the vicinity of a conical intersection of electronic energy surfaces and derive analytical expressions for the scattering matrix. The latter are valid when the scattering length that scales as square root(h) is small and a wave packet passes through the scattering region with a constant velocity. The analytical results are in excellent agreement with numerical simulations for a realistic set of parameters.     

Synthesis and research of electrochemical behavior of magnetic nanocomposites based on Fe3O4

The nanocomposites including magnetite nanoparticles, polymer coating and electrochemically active molecules were synthesized and investigated: poly(vinylbenzyl) chloride coating modified by quinoline; coating based on polypyrrole, silica coating modified by ferrocene derivative. All samples were investigated by the cyclic voltammetry method.     

Families of Lagrangian fibrations on hyperkähler manifolds

A holomorphic Lagrangian fibration on a holomorphically symplectic manifold is a holomorphic map with Lagrangian fibers. It is known (due to Huybrechts) that a given compact manifold admits only finitely many holomorphic symplectic structures, up to deformation. We prove that a given compact, simple hyperkähler manifold with _b2?7$b_2?7$ admits only finitely many deformation types of holomorphic Lagrangian fibrations. We also prove that all known hyperkähler manifolds are never Kobayashi hyperbolic.     

A formally Kähler structure on a knot space of a G 2-manifold

A knot space in a manifold M is a space of oriented immersions ${S^{1} \hookrightarrow M}$ up to Diff(S ¹). J.-L. Brylinski has shown that a knot space of a Riemannian threefold is formally Kähler. We prove that a space of knots in a holonomy G ₂ manifold is formally Kähler.     

High-pressure studies of optical dephasing in polymer glasses

The effect of high pressure on the optical dephasing of chromophores in organic polymers at low temperature is evaluated within the stochastic sudden jump two-level-system (TLS) model. The approximations within the "standard" TLS model cannot account for the observed pressure dependence of the pure dephasing rate without ad hoc assumptions about changes in the TLS density of states. However, the photon echo model of Geva and Skinner for disordered systems can be used to model pressure-dependent optical dephasing results for a variety of doped polymer systems without assuming changes in the TLS density of states. The relative importance of pressure-induced changes in TLS density, chromophore-TLS coupling, and TLS-phonon coupling is evaluated by fitting experimental high-pressure photon echo results to the TLS model.     

Thermal diffusivity of rhodamine 6G incorporated in silver nanofluid measured using mode-matched thermal lens technique

Dual beam mode-matched thermal lens method has been employed to measure the heat diffusion in nanofluid of silver with various volumes of rhodamine 6G, both dispersed in water. The important observation is an indication of temperature dependent diffusivity and that the overall heat diffusion is slower in the chemically prepared Ag sol compared to that of water. The experimental results can be explained assuming that Brownian motion is the main mechanism of heat transfer under the present experimental conditions. Light induced aggregation of the nanoparticles can also result in an anomalous diffusion behavior.