We report the use of photoassociative spectroscopy to determine the ground-state s-wave scattering lengths for the main bosonic isotopes of strontium, Sr-86 and Sr-88. Photoassociative transitions are driven with a laser red detuned by up to 1400 GHz from the S-1(0)-P-1(1) atomic resonance at 461 nm. A minimum in the transition amplitude for Sr-86 at -494 +/- 5 GHz allows us to determine the scattering lengths 610a(0)< a(86)< 2300a(0) for Sr-86 and a much smaller value of -1a(0)< a(88)< 13a(0) for Sr-88.

Using ab initio density-functional theory, the self-diffusion of adatom and dimer on fcc(100) metal surfaces are studied. For adatom diffusion, we find that the exchange mechanism is favored for Al, Ir, Ni, Pd, Pt and Au, while the hopping mechanism is favored for Rh, Cu, and Ag. Except for Ir/Ir(100), the exchange diffusion energy has a surprising large size-effect and decreases as the surface unit cell increases. This is due to the long-ranged strain-field created at the exchange transition state, which needs a larger cell to relax. The hopping diffusion energy, on the other hand, has a very small size-effect and keeps approximately the same value for various surface unit cells. For self-diffusion on lr(100), the formation of covalent bonds are found at the exchange transition state, and thus the exchange diffusion energy has a little size-effect. Our results also indicate that the exchange mechanism is energetically more favorable for dimer diffusion on fcc(100) surface whenever it is favored for adatom diffusion on fcc(100) surface.

Different cellular accumulations with distinct fluorescence properties of BMVC in cancer cells from normal cells allow us to establish a simple and economic method for the diagnosis of cancer cells. With using a light emitting diode to excite the BMVC molecule, microarray fluorescence analysis of a cell-based glass chip provides an easy method towards the detection of a limited number of cancer cells.

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Previous energetic considerations have led to the belief that carbon nanotubes (CNTs) of 4 Angstrom in diameter are the smallest stable CNTs. Using high-resolution transmission electron microscopy, we find that a stable 3 Angstrom CNT can be grown inside a multiwalled carbon nanotube. Density functional calculations indicate that the 3 Angstrom CNT is the armchair CNT(2,2) with a radial breathing mode at 787 cm(-1). Each end can be capped by half of a C(12) cage (hexagonal prism) containing tetragons.

The structure of a type of surface magic cluster is determined by a combination of scanning tunneling microscopy, density-functional calculations, and dynamical low energy electron diffraction. The diffraction method is applicable because these clusters created through hierarchical self-organization of Ga deposited onto a Si(111)-7x7 surface have identical size and structure and form an ordered array with exact translational symmetry. The unprecedented detailed structure information provided by the diffraction measurement is consistent with direct microscopic imaging and theoretical calculations.

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