thermal rearrangement of 7,7-dichloro-[a,c]-dibenzo-[4,1,0]-bicycloheptane (1) to 5,6-dichloro-5hdibenzo-[a,c]-cycloheptene (2) was studied in the solid phase and in solvents with different polarities. thefirst-order constants at various temperatures for the rearrangement process were evaluated from theabsorption time data. the activation parameters for this rearrangement were obtained from the...

A new group of ternary borides has been found that show either ferromagnetism or superconductivity. Their general formula is MRh(4)B(4) where M is a transition or rare-earth element. Their superconducting transition temperatures range from approximately 2.5 K for the Sm compound to approximately 12 K for the Lu compound.

We propose two coupled electron-hole sheets of few-layer graphene as a new nanostructure to observe superfluidity at enhanced densities and enhanced transition temperatures. For ABC stacked few-layer graphene we show that the strongly correlated electron-hole pairing regime is readily accessible experimentally using current technologies. We find for double trilayer and quadlayer graphene sheets...

C60 single crystals have been intercalated with CHCl3 and CHBr3 in order to expand the lattice. High densities of electrons and holes have been induced by gate doping in a field-effect transistor geometry. At low temperatures, the material turns superconducting with a maximum transition temperature of 117 K in hole-doped C60/CHBr3. The increasing spacing between the C60 molecules follows the ge...

The temperature-dependent infrared properties of θ-(BEDT-TTF)2RbZn(SCN)4 were investigated. In the temperatures above the metal-insulator (M-I) transition, the optical conductivity remains finite in the low energy region, but shows no conventional Drude feature typical of metals. Below the M-I transition temperature, the low-energy spectral weight is significantly reduced. An opening of optical...

The roughening phase diagram of the d=3 Ising model with uniaxially anisotropic interactions is calculated for the entire range of anisotropy, from decoupled planes to the isotropic model to the solid-on-solid model, using hard-spin mean-field theory. The phase diagram contains the line of ordering phase transitions and, at lower temperatures, the line of roughening phase transitions, where the...

A chalcogenide glass capable of infrared transmission which is either sulfur, selenium or tellurium based and consists of compositions of the formula MX+M.sub.2 'X.sub.3 +SiX.sub.2, wherein M is one of the metals calcium, strontium, barium, zinc and lead, and M' is either aluminum or gallium and X is either sulfur, selenium or tellurium. Aluminum or gallium chalcogenide acts to increase the cov...

Vortex matter in presence of disorder Eli Zeldov Department of Condensed Matter Physics, Weizmann Institute of Science, Israel Several examples of the recent progress in comprehension of the equilibrium properties of vortex matter will be presented. Using microscopic Hall sensors and vortex shaking by in-plane ac field, a thermodynamic evidence of a first-order disorder-driven transition at int...

Infrared visible sum frequency generation (SFG) spectroscopy has been used to study structure and melting transition temperatures of alkyl-side chain-acrylate comb polymers at air and solid interfaces. At the air interface, the SFG spectra show methyl bands and two transitions are observed: the first, near the bulk melting temperature, T(m), and the second 10-20 degrees C higher than T(m). The ...

The temperature-independent Wang-Landau Monte Carlo approach is implemented for an off-lattice model of flexible homopolymers and applied to the coil-globule and solidification transitions based on chain sizes up to N=300. An intermediate transformation from low-density liquid globule to high-density liquid globule is suggested. A scheme for identifying polymer structures representative of part...