3-Oxabicyclo[3,2,0]hepta-1,4-diene

3-Oxabicyclo[3,2,0]hepta-1,4-diene (3) has been synthesized by partial hydrogenation of 3-oxabicyclo-[3,2,0]hepta-1,4,6-triene (2)

Creation of Skyrmions in a Spinor Bose-Einstein Condensate

We propose a scheme for the creation of skyrmions (coreless vortices) in a Bose-Einstein condensate with hyperfine spin F=1. In this scheme, four traveling-wave laser beams, with Gaussian or Laguerre-Gaussian transverse profiles, induce Raman transitions with an anomalous dependence on the laser polarization, thereby generating the optical potential required for producing skyrmions.Comment: 5 pages, 2 figures, RevTe

Separation of Diastereomers, Structural Isomers, and Homologs of n5 -Cyclopentadienyl Cobalt and Dinuclear Molybdenum Complexes by Reverse Phase High Performance Liquid Chromatography Using Deoxygenated Solvents

High Performance Liquid Chromatography (HPLC) is being used as an analytical and preparative tool for the characterization and isolation of a series of air-sensitive organometallic compounds, Reverse phase chranatography with octadecylsilyl-modified silica (ODS) as a stationary phase and polar mobile phases saturated with argon are employed in the separation of products

Quantum Vortex in a Vectorial Bose-Einstein Condensate

Quantum vortices in the multi-component Bose-Einstein condensation (BEC) are investigated theoretically. It is found that three kinds of the vortex configurations are possible and their physical properties are discussed in details, including the density distribution and the spin texture. By using the Bogoliubov theory extended to the three component BEC, the collective modes for these vortices are evaluated. The local vortex stability for these vortices are examined in light of the existence of the negative eigenvalue, yielding a narrow magnetization window for the local intrinsic stable region where the multi-components work together to stabilize a vortex in a self-organized way.Comment: 8 pages, 14 eps figure

Spin and Charge Structure Factor of the 2-d Hubbard Model

The spin and charge structure factors are calculated for the Hubbard model on the square lattice near half-filling using a spin-rotation invariant six-slave boson representation. The charge structure factor shows a broad maximum at the zone corner and is found to decrease monotonically with increasing interaction strength and electron density and increasing temperature. The spin structure factor develops with increasing interaction two incommensurate peaks at the zone boundary and along the zone diagonal. Comparison with results of Quantum Monte Carlo and variational calculations is carried out and the agreement is found to be good. The limitations of an RPA-type approach are pointed out.Comment: 18 pages, revtex, 13 postscript figures, submitted to Phys. Rev.

Quantum critical point in a periodic Anderson model

We investigate the symmetric Periodic Anderson Model (PAM) on a three-dimensional cubic lattice with nearest-neighbor hopping and hybridization matrix elements. Using Gutzwiller's variational method and the Hubbard-III approximation (which corresponds to the exact solution of an appropriate Falicov-Kimball model in infinite dimensions) we demonstrate the existence of a quantum critical point at zero temperature. Below a critical value $V_c$ of the hybridization (or above a critical interaction $U_c$) the system is an {\em insulator} in Gutzwiller's and a {\em semi-metal} in Hubbard's approach, whereas above $V_c$ (below $U_c$) it behaves like a metal in both approximations. These predictions are compared with the density of states of the $d$- and $f$-bands calculated from Quantum Monte Carlo and NRG calculations. Our conclusion is that the half-filled symmetric PAM contains a {\em metal-semimetal transition}, not a metal-insulator transition as has been suggested previously.Comment: ReVteX, 10 pages, 2 EPS figures. Minor corrections made in the text and in the figure captions from the first version. More references added. Accepted for publication in Physical Review

Biscarbyne Clusters by Alkyne Cleavage: A General Reaction

We describe a general synthesis and preliminary physical and chemical properties of biscarbyne clusters prepared by a conceptually most simple route, the direct cleavage of alkynes