He: Vortices and turbulence PACS 61.46.Km -Structure of nanowires nanorods (long, free or loosely attached, quantum wires rods, but not gate-isolated embedded wires)Abstract -We demonstrate that laser ablation a gold target immersed in superfluid normal fluid helium leads to the formation elongated nano-fragments.In phase these nano-fragments aggregate into filaments with extremely large aspect ratios displaying metallic electric conductivity.We attribute this unusual structure coalescence...

The Kennard-Stepanov relation describes a thermodynamic, Boltzmann-type scaling between the absorption and emission spectral profiles of an absorber, which applies in many liquid state dye solutions as well semiconductor systems. Here we examine spectra rubidium atoms dense argon buffer gas environment. We demonstrate that is fulfilled collisionally broadened atomic system. Our experimental findings are supported by simple theoretical model.

Metallic nanoparticles trapped at a free surface of superfluid helium coalesce into centimeter-sized networks.

We present a new theoretical analysis of the strongly suppressed F- and M-dependent Stark shifts Cs ground-state hyperfine structure. Our treatment uses third-order perturbation theory including off-diagonal interactions not considered in earlier treatments. A numerical evaluation sum using bound states up to n = 200 yields tensor polarizabilities α2(6S1/2,F) which are good agreement with experimental values, thereby bridging 40-year-old gap between experiments theory. have further found...

It is demonstrated that the velocity-selective optical pumping/saturation resonances of reduced absorption in a Rb vapor nanocell with thickness L = λ, 2λ, and 3λ (resonant wavelength λ 780 nm) allow for complete elimination crossover (CO) resonances. We observe well-pronounced corresponding to F g 3 → e 2, 3, 4 hyperfine transitions 85Rb D2 line widths close natural width. A small CO resonance located midway between appears only ≥ 4λ. The (λ 852 Cs exhibits similar behavior. From amplitude...

Electrically charged metallic micro- and nanoparticles are trapped under a free surface of superfluid He in vertical static electric field. We observe deformation the liquid form Taylor cone emission helium jet (electrospray). Our numeric calculations reproduce shape cone.

A little more than a decade ago our team extended the field of defect spectroscopy in cryocrystals to solid He4 matrices, both their body-centered cubic (bcc) and hexagonal close-packed (hcp) configurations. In this review paper we survey pioneering activities compare results those obtained related fields doped superfluid helium nanodroplets, domains developed parallel own efforts. We present experimental details sample preparation different spectroscopic techniques. Experimental purely...

Copper atoms and molecules are laser ablated into bulk liquid solid helium, the emission spectra of excited D→X, B→X, a→X transitions Cu2 observed to exhibit clearly resolved vibrational bands. Surprisingly, for D→X B→X transitions, no differences were superfluid He at 1.5 K, normal 2.65 or K higher pressures about 30 bars. An interpretation based on bubble model indicates that interaction with matrix is much weaker than in case alkali atoms. Compared other rare gas matrices, line shifts...

We have observed several new spectral features in the fluorescence of cesium atoms implanted hcp phase solid helium following laser excitation to ${6}^{2}P$ states. Based on calculations emission spectra using semiempirical Cs-He pair potentials newly discovered lines can be assigned decay specific ${\mathrm{C}\mathrm{s}}^{*}{\mathrm{H}\mathrm{e}}_{n}$ exciplexes: an apple-shaped $\mathrm{C}\mathrm{s}(A{\ensuremath{\Pi}}_{3/2}){\mathrm{H}\mathrm{e}}_{2}$ and a dumbbell-shaped...

We present a theoretical and experimental study of the laser-induced formation process emission spectra Cs*He(n) exciplexes in hcp bcc phases solid helium. Two different exciplex molecules are detected: linear triatomic Cs*He2, which can exist two electronic states: APi(1/2) BPi(3/2), larger complex, where six or seven He atoms form ring around single cesium atom 6P(1/2) state. A model is presented, allows interpretation experimentally observed spectra.

We have observed bulk solidification of 4He induced by nucleation on positive alkali ions in pressurized superfluid helium. The are extracted into the liquid from alkali-doped solid He a static electric field. experiments prove existence charged particles structure composed doped that was recently shown to coexist with helium below pressure. This supports our earlier suggestion Coulomb interaction surrounded shell (snowballs) and electrons trapped spherical cavities (electron bubbles),...

We present an experimental and theoretical study of the 2D dynamics electrically charged nanoparticles trapped under a free surface superfluid helium in static vertical electric field. focus on particles driven by interaction with quantized vortices terminating at surface. identify two types particle trajectories associated vortex structures: linear pinned bottom container half-ring travelling along liquid.

The optical rectification effect is observed in periodically structured metal films (metasurfaces) with broken inversion symmetry. It found that the finite width of metasurface and proximity its edges also provide a symmetry-breaking mechanism, adding to current, which further enhanced at surface plasmon polariton resonances. By position- angle-resolved measurements we show this mechanism more efficient than symmetry breaking achieved either by oblique incidence laser light or nonsymmetric...

We report the observation of emission spectra from Rb*He_n exciplexes in solid 4He. Two different excitation channels were experimentally identified, viz., exciplex formation via laser to atomic 5P3/2 and 5P1/2 levels. While former channel was observed before liquid helium, on helium nanodroplets gas by groups, latter creation mechanism occurs only or gaseous above 10 Kelvin. The experimental results are compared theoretical predictions based extension a model, used earlier us for...

We present a systematic experimental study of the absorption and fluorescence spectra $6{S}_{1∕2}\text{\ensuremath{-}}6{P}_{1∕2}$ transition in Cs atoms isolated solid $^{4}\mathrm{He}$ matrices. The bubble model developed earlier for alkali-metal liquid He is revised applied to system. analysis dependencies wavelengths on pressure (cubic hexagonal) environments leads us modify by taking elastic deformation atomic into account.

We present an exhaustive overview of optical absorption and laser-induced fluorescence lines Ba atoms in liquid solid helium matrices visible near-infrared spectral ranges. Due to the increased density isolated atoms, we have found a large number that were not observed condensed before. also measured lifetimes metastable states. The lowest ${}^{3}{D}_{1}$ state has lifetime 2.6 s can be used as intermediate two-step excitations high-lying Various matrix-induced radiationless population...

We discuss the interaction between nanometer-sized defects (atomic bubbles) and elementary excitations (phonons) in quantum fluids solids. observe that optical embedded metal atoms induce bubble expansions/contractions create strongly localized phonon wave packets matrix. derive structure dynamics of these vibronic from experimental laser-induced fluorescence spectra Au Cu liquid solid He. The atomic vibrations are found to be damped on 50 Å 5 ps scales agreement with pure hydrodynamic estimations.

We present comparative experimental and theoretical studies of the absorption fluorescence spectra alkali-metal dimer molecules Cs(2) RbCs immersed in a solid helium matrix, thereby extending our recent observations Rb(2) (4)He. The laser-excited molecular states are mostly quenched by interaction with He matrix. quenching efficiently populates second lowest excited state molecule, i.e., (1) (3)Π((u)) that is metastable homonuclear dimers. Molecular excitation emission bands modeled...

We present an experimental study of the laser-induced fluorescence spectra Cu atoms in bulk liquid and solid helium matrices as well dense plasma created by laser ablation copper helium. observe transitions valence electron inner-shell electrons. The former produce structureless line shapes, a large broadening, blueshift. latter practically are not shifted with respect to free atom possess substructure consisting zero-phonon phonon wings. suggest qualitative interpretation observed based on...

We report an experimental and theoretical study of the motion metallic micro- nanoparticles in cryogenic superfluid helium presence a static electric field. Depending on polarity applied field, system is charged with large number positive ions or free electrons. For electrons, we observe formation negative charge layer above surface liquid He shuttle-like particles between this positively bottom electrode. ions, space created particle resembles bouncing off (negatively charged) The...

Atomic ions and free electrons embedded in condensed helium play important role modern research on quantum fluids solids. Here we present experimental theoretical study of Ba+ cations immersed superfluid He. We observe laser-induced fluorescence injected into liquid He from the plasma radio frequency discharge He-Ba gas mixture. The structure trapping site is studied theoretically frame atomic bubble model making use ab initio - pair potentials available literature. Calculated spectra ion...

We report the results of a high-resolution laser-spectroscopy study dysprosium atoms injected into superfluid $^{4}\mathrm{He}$. A special attention is paid to transitions between inner $4f$ and $5d$ electronic shells Dy. The characteristic gap observed zero-phonon line phonon wing in experimental excitation spectrum that arises due peculiar structure phonon-roton He. This observation resolves longstanding discrepancy studies bulk He nanodroplets.