Search results for "GASES"
showing 10 items of 1098 documents
Spatial dependence of the pairing field calculated with bare and induced interactions
2009
The interaction induced by the exchange of low-lying surface vibrations between pairs of orbitals close to the Fermi surface provides an important contribution to pairing correlations in superfluid nuclei. We study the spatial dependence of the pairing field obtained adding the bare and induced interaction in 120Sn.
Interacting Rubidium and Caesium Atoms
2007
Binary mixtures of ultracold atoms are of great interest in the research field of quantum optics and are studied by several groups aiming at different applications. This paper works with rubidium and caesium, which are simultaneously stored in a magnetic trap. Species-selective microwave cooling is used on the rubidium groundstate hyperfine transition. Caesium is sympathetically cooled via elastic collisions with rubidium. When cooling down the mixture to temperatures below 1 muK, below 4 muK we observe strong losses of caesium. Analysing the dynamics of sympathetic cooling, lower limit for the modulus of the rubidium-caesium triplet s-wave scattering length is estimated.
Trapped ion density distribution in the presence of He-buffer gas
1981
The spatial density distribution of Ba+ ions, confined in a rf quadrupole trap, has been measured by laser scanning across the trap. This allows to determine the ion temperature, assuming thermal equilibrium. Under UHV conditions the average ion energy has been found to be one tenth of the trap potential well depth. Collisions with He at pressures up to 5×10−6 mbar reduce the ion temperature by a factor of 3.
Calcium dicaesium silver thiocyanate dihydrate.
2001
The title compound, CaCs2[Ag2(SCN)6]·2H2O, forms a continuous structure where the Ag atoms form chains with S atoms in the c-axis direction. The chains are bonded together through Cs and Ca atoms. The crystal water of the structure is bonded to the Ca atoms, which lie on centers of symmetry.
Feasibility of In-Trap Conversion Electron Spectroscopy
2001
We have used REXTRAP at ISOLDE to test the feasibility of in-trap electron spectroscopy. The results of calculations, experiments with various electron sources as well as a first test with trapped radioactive ions are presented.
High-spin states in tetrahedral X4 clusters (X = H, Li, Na, K)
2010
The high-spin electronic states for lithium, sodium, and potassium four-atom clusters were studied. In particular, we performed coupled cluster geometry optimization of the quintet state in tetrahedral geometry. The quintet state of these systems is characterized by having all the valence electron Unpaired, giving rise to the so-called no-pair bonding. Single-point full configuration interaction computations on the equilibrium geometries for the various Clusters are also presented. The analysis of the valence orbitals in a localized representation confirms the importance of the p atomic orbitals to explain this unusual type of bond. (C) 2009 Wiley Periodicals, Inc. Int J Quantum Chem 110: 8…
Small Clusters Made of Helium Atoms
2003
Helium atoms interact very weakly through a van der Waals potential. Nevertheless, they are able to form aggregates or drops with a small number of atoms. This work analyzes the stability of clusters made of 4He atoms, of bosonic nature, clusters made of 3He atoms, of fermionic nature and also mixed aggregates with both kinds of constituents. Some of these drops are predicted to be unstable.
"Table 1" of "Search for promptly produced heavy quarkonium states in hadronic Z decays"
1996
The analysis of hadrons (from X) provides to distinguish of the various decay modes of Z-boson (see text).
Fermi-type interaction in molecular and atomic Hamiltonians. Application to molecular systems and Bose-Einstein condensates.
2008
International audience; We present a simple prescription to build phenomenological Hamiltonians describing Fermi-type interactions and apply the developed formalism to two distinct physical systems. First, in a very simple way, we derive equations describing time dynamics of two coherently coupled Bose-Einstein condensates. Further, for bent XY2 molecules, we reproduce all the experimental data with an excellent precision.
Moдель демкова–кунике для ассоциации холодных атомов: режим слабого взаимодействия.
2009
International audience; We examine the nonlinear dynamics of molecule formation at coherent photo- and magneto-association of an atomic Bose–Einstein condensate when the external field configuration is defined by the quasi-linear level crossing Demkov–Kunike model, characterized by a bell-shaped pulse and finite variation of the detuning. We present an approach to construct an approximation describing the temporal dynamics of the molecule formation in the weak interaction regime and apply the developed method to the nonlinear Demkov–Kunike problem. The presented approximation, written as a scaled solution to the linear problem associated to the nonlinear one we treat, contains adjustable pa…