A5066030678- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Advanced Sensor and Energy Harvesting Materials
- Electrostatics and Colloid Interactions
- Laser-Matter Interactions and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Molecular Junctions and Nanostructures
- nanoparticles nucleation surface interactions
- Spectroscopy and Laser Applications
- Mass Spectrometry Techniques and Applications
- Ferroelectric and Piezoelectric Materials
- Spectroscopy and Quantum Chemical Studies
- Nanowire Synthesis and Applications
- Surface and Thin Film Phenomena
- Modular Robots and Swarm Intelligence
- Supramolecular Self-Assembly in Materials
- Electron and X-Ray Spectroscopy Techniques
- Advanced Physical and Chemical Molecular Interactions
- Semiconductor Quantum Structures and Devices
- Calcium Carbonate Crystallization and Inhibition
- Lipid Membrane Structure and Behavior
- Acoustic Wave Resonator Technologies
- ZnO doping and properties
- Paleontology and Stratigraphy of Fossils
- Analytical Chemistry and Chromatography
Tel Aviv University
2021
Weizmann Institute of Science
1999-2020
Aarhus University
2009-2010
A strong inhomogeneous static electric field is used to spatially disperse a supersonic beam of polar molecules, according their quantum state. We show that the molecules residing in lowest-lying rotational states can be selected and as targets for further experiments. As an illustration, we demonstrate unprecedented degree laser-induced one-dimensional alignment $(⟨{cos}^{2}{\ensuremath{\theta}}_{2\mathrm{D}}⟩=0.97)$ orientation state-selected iodobenzene molecules. This method should...
Despite their ionic nature, many layered diatomic crystals avoid internal electric polarization by forming a centrosymmetric lattice at optimal anti-parallel van-der-Waals stacking. Here, we report stable ferroelectric order emerging the interface between two naturally-grown flakes of hexagonal-boron-nitride, which are stacked together in metastable non-centrosymmetric parallel orientation. We observe alternating domains inverted normal polarization, caused lateral shift one site domains....
Supersonic beams of polar molecules are deflected using inhomogeneous electric fields. The quantum-state selectivity the deflection is used to spatially separate according their quantum state. A detailed analysis and obtained selection presented. rotational temperatures molecular determined from spatial beam profiles all approximately 1 K. Unprecedented degrees laser-induced alignment (<cos2 theta2D>=0.972) orientation iodobenzene demonstrated when state-selected samples used. Such oriented...
A strong inhomogeneous static electric field is used to spatially disperse a rotationally cold supersonic beam of 2,6-difluoroiodobenzene molecules according their rotational quantum state. The in the lowest lying states are selected and as targets for 3-dimensional alignment orientation. induced adiabatic regime with an elliptically polarized, intense laser pulse orientation by combined action weak field. We show that degree strongly enhanced when state-selected molecules, rather than...
Abstract 1D core–shell heterojunction nanostructures have great potential for high‐performance, compact optoelectronic devices owing to their high interface area volume ratio, yet bottom‐up assembly toward scalable fabrication remains a challenge. Here the site‐controlled growth of aligned CdS–CdSe nanowalls is reported by combination surface‐guided vapor–liquid–solid horizontal and selective‐area vapor–solid epitaxial growth, integration into photodetectors at wafer‐scale without postgrowth...
The energy-resolved rate coefficient for the dissociative recombination (DR) of $\mathrm{H}_{3}{}^{+}$ with slow electrons has been measured by storage-ring method using an ion beam produced from a radiofrequency multipole trap, employing buffer-gas cooling at 13 K. electron energy spread merged-beams measurement is reduced to $500\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$ cryogenic GaAs photocathode. This and previous cold-$\mathrm{H}_{3}{}^{+}$ jointly confirm capability storage rings,...
Merging an HD+ beam with velocity matched electrons in a heavy ion storage ring we observed rapid cooling of the rotational excitations ions by superelastic collisions (SEC) electrons. The process is well described using theoretical SEC rate coefficients obtained combining molecular R-matrix approach adiabatic nuclei rotation approximation. We verify DeltaJ=-2 coefficients, which are predicted to be dominant as opposed DeltaJ=-1 rates and amount (1-2)x10;{-6} cm;{3} s;{-1} for initial...
Measurements on the energetic structure of dissociative recombination rate coefficient in millielectronvolt range are described for ions produced lowest rotational levels by collisional cooling and stored as a fast beam magnetic storage ring TSR (Test Storage Ring). The observed resonant is consistent with that found previously at facility CRYRING Stockholm, Sweden; theoretical predictions yield good agreement overall size coefficient, but do not reproduce detailed structure. First studies...
The collision-energy resolved rate coefficient for dissociative recombination of HD${}^{+}$ ions in the vibrational ground state is measured using photocathode electron target at heavy-ion storage ring TSR. Rydberg resonances associated with rovibrational excitation core are scanned as a function collision energy an instrumental broadening below 1 meV low-energy limit. measurement compared to calculations multichannel quantum defect theory, accounting rotational structure and interactions...
The key to functionalize of engineered molecularly nanometer thick films lies in the ability reproducibly control their structure. A number factors influence film morphology self-assembled on solid or liquid surfaces, such as structure molecules/particles, wetting, solvent hydrodynamics, and evaporation. An important example is deposition amphiphilic molecules from a volatile solution, onto water surface at monolayer coverage. Upon evaporation, myriad microscopic two-dimensional (2D)...
A three-dimensional imaging technique installed at the Heidelberg Test Storage Ring (TSR) has been used to investigate three-body breakup channels occurring in dissociative recombination process of methylene ion ${\text{CH}}_{2}^{+}$. By selecting dissociation planes perpendicular molecular beam direction kinematics could be measured with unprecedented momentum resolution. Release energies, relative branching ratio, and kinematical correlations between three fragments were determined for two...
Local surface photovoltage imaging with a scanning tunneling microscope is used to demonstrate two types of local Fermi-level pinning next single adsorbate or defect, taking advantage the tip-induced band bending due lack gap states at clean GaAs(110) surfaces. The energy cesium adatom location was determined be $0.56\ifmmode\pm\else\textpm\fi{}0.04\mathrm{eV}$ above valence-band maximum (VBM), while for As vacancy, Fermi level cannot go below top filled state,...
A pulsed IR laser beam was used to align a peptide at the air–water interface. This designed form cyclic β-strand dimer through Glu–Lys interactions in solution, which, when spread onto water, yielded self-assembled β-sheet bilayer (see picture) following solvent evaporation. During this process illumination with linearly polarized light induced formation of an aligned crystalline film, whereas circular polarization did not. Detailed facts importance specialist readers are published as...
We employed atomically-resolved surface photovoltage (SPV) imaging with a scanning tunneling microscope, using super- and sub-band gap energy photons, to map the potential distribution around single As vacancy at p-GaAs(110) surface. While super-band (532 nm) SPV reflects band bending (including tip-induced effect) in dark, (1064 shows change due charge injection into defect. conclude that introduces state, ∼0.63 eV above valence maximum, has be filled two electrons maintain neutrality....
Rotational cooling of HD+ by superelastic collisions (SEC) with electrons was observed at the Heidelberg test storage ring merging a beam rotationally hot ions an electron zero relative energy. Neutral fragments resulting from DR events were recorded different densities using high resolution imaging detector and large-area, energy sensitive detector. The data allowed to deduce time dependence population three groups rotational angular momentum states J built on vibrational ground state ion...
The induction of homogeneous and oriented ice nucleation has to date not been achieved. Here, we report induced from millimeter sized supercooled water drops illuminated by ns-optical laser pulses well below the ionization threshold making use particular beam configurations polarizations. Employing a 100 ps synchrotron x-ray pulse ns after each pulse, an unambiguous correlation was observed between directions symmetry fields that H-bonding arrays crystals. Moreover, analysis diffraction data...
Ordnung durch Licht: Ein Peptid, das in Lösung Glu-Lys-Wechselwirkungen ein cyclisches β-Strangdimer bildet, ergab beim Spreizen auf Wasser nach dem Verdunsten des Lösungsmittels eine selbstorganisierte β-Faltblatt-Doppelschicht (siehe Schema). Wurde dabei fast linear polarisiertes Laserlicht eingestrahlt, entstand ausgerichteter kristalliner Film, circulare Polarisation dagegen bewirkte nichts. Detailed facts of importance to specialist readers are published as ”Supporting Information”....
Potential variations on semiconductor surfaces are often mapped using a combination of constant current topographic and local surface photovoltage (SPV) imaging. SPV imaging provides direct measurement surface-potential at large lateral distances from charged defect or adsorbate. However, directly above the defect, in signal need to be interpreted terms screening, traps, band bending. We have examined these effects isolated oxygen atoms GaAS(110) surface, which is free states. interpret...