3,264 research outputs found
Theory of long-range ultracold atom-molecule photoassociation
The creation of ultracold molecules is currently limited to diatomic species.
In this letter we present a theoretical description of the photoassociation of
ultracold atoms and molecules to create ultracold excited triatomic molecules,
thus being a novel example of light-assisted ultracold chemical reaction. The
calculation of the photoassociation rate of ultracold Cs atoms with ultracold
Cs molecules in their rovibrational ground state is reported, based on the
solution of the quantum dynamics involving the atom-molecule long-range
interactions, and assuming a model potential for the short-range physics. The
rate for the formation of excited Cs molecules is predicted to be
comparable with currently observed atom-atom photoassociation rates. We
formulate an experimental proposal to observe this process relying on the
available techniques of optical lattices and standard photoassociation
spectroscopy.Comment: 5 pages, 3 figure
Current and future perspectives of positronium and muonium spectroscopy as dark sectors probe
Positronium and Muonium are purely leptonic atoms and hence free of an
internal sub-structure. This qualifies them as potentially well suited systems
to probe the existence of physics beyond the Standard Model. We hence carry out
a comprehensive study of the sensitivity of current Positronium and Muonium
precision spectroscopy to several new physics scenarios. By taking properly
into account existing experimental and astrophysical probes, we define clear
experimental targets to probe new physics via precise spectroscopy. For
Positronium we find that, in order for the spectroscopy bounds to reach a
sensitivity comparable to the electron gyromagnetic factor, an improvement of
roughly five orders of magnitude from state-of-the-art precision is required,
which would be a challenge based on current technology. More promising is
instead the potential reach of Muonium spectroscopy: in the next few years
experiments like Mu-MASS at PSI will probe new regions of the parameter space
testing the existence of medium/short range (MeV and above) spin-dependent and
spin-independent dark forces between electrons and muons.Comment: 8 pages, 6 figures. Version changed to match journal version. Figures
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Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity
Indexación: Web of ScienceTheoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices like the electrophilic and nucleophilic Parr functions, as the most relevant indices for the study of organic reactivity, are discussed.http://www.mdpi.com/1420-3049/21/6/74
Créditos ECTS una nueva oportunidad para replantear el practicum y la formación inicial del profesorado
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