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Electric deflection measurements on liquid helium nanodroplets doped with individual polar molecules demonstrate that the cold superfluid matrix enables full orientation of the molecular dipole along the external field. This translates into…

原子与分子团簇 · 物理学 2016-11-21 Daniel J. Merthe , Vitaly V. Kresin

Focused ion beam irradiation of metastable Fe$_{78}$Ni$_{22}$ thin films grown on Cu(100) substrates is used to create ferromagnetic, body-centered-cubic patterns embedded into paramagnetic, face-centered-cubic surrounding. The structural…

Optical tweezers, the three-dimensional confinement of a nanoparticle by a strongly focused beam of light, have been widely employed in investigating biomaterial nanomechanics, nanoscopic fluid properties, and ultrasensitive detections in…

When weakly-bound complexes are multiply excited by intense electromagnetic radiation, energy can be exchanged between neighboring atoms through a type of resonant interatomic Coulombic decay (ICD). This decay mechanism due to multiple…

Here, we report the observation of electron transfer mediated decay (ETMD) involving Mg clusters embedded in helium nanodroplets which is initiated by the ionization of helium followed by removal of two electrons from the Mg clusters of…

Molecular dynamics simulations have been performed on pure liquid water, aqueous solutions of sodium chloride, and polymer solutions exposed to a strong external electric field with the goal to gain molecular insight into the structural…

软凝聚态物质 · 物理学 2016-08-08 I. Nezbeda , J. Jirsák , F. Moučka , W. R. Smith

The stability of two-component clusters consisting of light (Na or K) and heavy (Rb or Cs) alkali atoms formed on helium nanodroplets is studied by femtosecond laser ionization in combination with mass spectrometry. Characteristic stability…

原子与分子团簇 · 物理学 2011-12-19 G. Droppelmann , M. Mudrich , C. P. Schulz , F. Stienkemeier

Helium nanodroplets doped with polar molecules are studied by electrostatic deflection. This broadly applicable method allows even polyatomic molecules to attain sub-Kelvin temperatures and nearly full orientation in the field. The…

原子与分子团簇 · 物理学 2019-07-26 John W. Niman , Benjamin S. Kamerin , Daniel J. Merthe , Lorenz Kranabetter , Vitaly V. Kresin

Current advances in ultrafast electron microscopy make it possible to combine optical pumping of a nanostructure and electron beam probing with sub{\aa}ngstrom and femtosecond spatiotemporal resolution. We present a theory predicting that…

Helium nanodroplets, commonly regarded as the "nearly ideal spectroscopic matrix", are being actively studied for more than two decades now. While they mostly serve as cold, weakly perturbing and transparent medium for high-resolution…

原子与分子团簇 · 物理学 2015-03-03 M. Mudrich , F. Stienkemeier

When fragile molecules such as glycine, polyglicine, alkanes, and alkanethiols are embedded in liquid helium nanodroplets, electron-impact ionization of the beam leads to fragmentation which is as extensive as that of isolated gas-phase…

原子与分子团簇 · 物理学 2008-02-23 Yanfei Ren , Vitaly V. Kresin

Space resolved concentrations of helium He metastable atoms in an atmospheric pressure radio-frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. The spatial profile of metastable atoms in the volume…

等离子体物理 · 物理学 2015-05-28 B Niermann , T Hemke , N Y Babaeva , M Böke , M J Kushner , T Mussenbrock , J Winter

Two-photon photoassociation of hot magnesium atoms by femtosecond laser pulses, creating electronically excited magnesium dimer molecules, is studied from first principles, combining \textit{ab initio} quantum chemistry and molecular…

Doping a helium nanodroplet with a tiny xenon cluster of a few atoms only, sparks complete ionization of the droplet at laser intensities below the ionization threshold of helium atoms. As a result, the intrinsically inert and transparent…

原子与分子团簇 · 物理学 2009-03-25 Alexey Mikaberidze , Ulf Saalmann , Jan M. Rost

Superfluid He nanodroplets resonantly excited by extreme ultraviolet (XUV) pulses exhibit complex relaxation dynamics, including the formation of metastable excited He$^*$ atoms trapped in bubbles, the desorption of excited atoms from the…

We report on the realization of Bose-Einstein condensation of metastable helium-4. After exciting helium to its metastable state in a novel pulse-tube cryostat source, the atomic beam is collimated and slowed. We then trap several 10^8…

We have studied the cooling dynamics, formation process and geometric structure of mesoscopic crystals of externally produced magnesium ions in a Penning trap. We present a cooling model and measurements for a combination of buffer gas…

原子物理 · 物理学 2016-10-19 T. Murboeck , S. Schmidt , G. Birkl , W. Noertershaeuser , R. C. Thompson , M. Vogel

The dynamics of vibrational wave packets excited in K$_2$ dimers attached to superfluid helium nanodroplets is investigated by means of femtosecond pump-probe spectroscopy. The employed resonant three-photon-ionization scheme is studied in…

原子与分子团簇 · 物理学 2009-11-11 P. Claas , G. Droppelmann , C. P. Schulz , M. Mudrich , F. Stienkemeier

A supersolid is a counter-intuitive state of matter that combines the frictionless flow of a superfluid with the crystal-like periodic density modulation of a solid. Since the first prediction in the 1950s, experimental efforts to realize…

Using extreme-ultraviolet attosecond-pulse-trains, we investigate the photoionization dynamics of a Helium atom in the presence of moderately-strong (~10^12 W/cm^2) femtosecond laser pulses. The electronic structure of a laser-dressed atom…

原子物理 · 物理学 2011-08-02 Niranjan Shivaram , Henry Timmers , Xiao-Min Tong , Arvinder S. Sandhu