60 Garden Street, Cambridge, Massachusetts 02138 (March 1, 1999) About fifty years ago two important papers appeared describing novel interactions. One, by Casimir, discussed the case of two interacting walls [1] and the other, by Casimir and Polder, considered the interactions between an atom and a wall and between two atoms [2]. The history and some of the many interesting aspects of these in...

In this research, some of the inorganic complexes of uranyl with N- donor ligandswere synthesized. Complexes were characteriezed by FT-IR and UV spectra, ¹HNMR,¹³CNMR and some physical properties. The uranyl unit (UO2) is composed of a center ofuranium atom with the charge (+6) and two oxygen atom by forming two U=O double bonds.The structure is linear (O=U=O, 180) and usually stable. So other ...

We present an atomistic tight-binding approach to calculating the electronic structure of semiconductor nanostructures. We start by deriving the strain distribution in the structure using the valence force field model. The strain field is incorporated into the tight-binding electronic structure calculation carried out in the frame of the effective bond orbital model and the fully atomistic sp3d...

Frictionless atom cooling in harmonic traps is formulated as a time-optimal control problem and a synthesis of optimal controlled trajectories is obtained.

At PTB we have developed an optical frequency standard based on laser cooled calcium atoms. A laser is frequencystabilized to the intercombination transition at a wavelength of 657 nm by means of time-domain atom interferences. The dependence of its frequency on various parameters was investigated by using different excitation schemes corresponding to phase sensitive and frequency sensitive ato...

the storage capacity of hydrogen on na-decorated born nitride nanotubes (bnnts) is investigated by using density functional theory within quantum espresso and gaussian 09. the results obtained predict that a single na atom tends to occupy above the central region of the hexagonal rings in (5,0) and (3,3) bnnt structures with a binding energy of -2.67 and -4.28 ev/na-atom respectively. when a si...

The complex of Ce(III), [ Ce (PHENSC) (H 0) ] (C10 ) , was synthesized using the PHENSC, a hexadentate ligand,2,9-diformyl-1,lO- Phenanthroline bis (semicarbazone), and characterized by X-ray diffraction. The cerium atom has an unusual coordination number of ten involving six donor atoms of the planar ligand in the equatorial plane and four oxygen atoms from four axial water molecules. The...