The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

R E Packard - One of the best experts on this subject based on the ideXlab platform.

Wei Kong - One of the best experts on this subject based on the ideXlab platform.

  • communication electron diffraction of ferrocene in Superfluid Helium droplets
    Journal of Chemical Physics, 2016
    Co-Authors: Jie Zhang, Yunteng He, Wei Kong
    Abstract:

    We report electron diffraction of ferrocene doped in Superfluid Helium droplets. By taking advantage of the velocity slip in our pulsed droplet beam using a pulsed electron gun, and by doping with a high concentration of ferrocene delivered via a pulsed valve, we can obtain high quality diffraction images from singly doped droplets. Under the optimal doping conditions, 80% of the droplets sampled in the electron beam are doped with just one ferrocene molecule. Extension of this size selection method to dopant clusters has also been demonstrated. However, incomplete separation of dopant clusters might require deconvolution and modeling of the doping process. This method can be used for studies of nucleation processes in Superfluid Helium droplets.

  • electron diffraction of Superfluid Helium droplets
    Journal of Physical Chemistry Letters, 2014
    Co-Authors: Jie Zhang, Yunteng He, William M Freund, Wei Kong
    Abstract:

    We present experimental results of electron diffraction of Superfluid Helium droplets and droplets doped with phthalocyanine gallium chloride and discuss the possibility of performing the same experiment with a laser aligned sample. The diffraction profile of pure droplets demonstrates dependence on the nozzle temperature, that is, on the average size of the droplets. Larger clusters demonstrate faster decay with increasing momentum transfer, whereas smaller clusters converge to isolated gas phase molecules at source temperatures of 18 K and higher. Electron diffraction of doped droplets shows similar modified molecular scattering intensity as that of the corresponding gas phase molecules. On the basis of fittings of the scattering profile, the number of remaining Helium atoms of the doped droplets is estimated to be on the order of hundreds. This result offers guidance in assessing the possibility of electron diffraction from laser aligned molecules doped in Superfluid Helium droplets.

Y Sato - One of the best experts on this subject based on the ideXlab platform.

  • josephson effects in Superfluid Helium
    2019
    Co-Authors: Y Sato, E Hoskinson, R E Packard
    Abstract:

    Two reservoirs of Superfluid Helium can be weakly coupled together to form a neutral matter analog of superconducting Josephson junctions. In this chapter, we present an overview of the development of the field of Josephson effects in Superfluid Helium, reviewing both the experimental and theoretical milestones that led to our current understanding. We discuss the physics of these systems with emphasis on the quantum oscillations that result from varying the coupling strength. We review the principles of Superfluid Helium quantum interference devices (SHeQUID) and some novel fundamental applications of this new technology.

  • Superfluid Helium quantum interference devices physics and applications
    Reports on Progress in Physics, 2012
    Co-Authors: Y Sato, R E Packard
    Abstract:

    We present an overview of recent developments related to Superfluid Helium quantum interference devices (SHeQUIDs). We discuss the physics of two reservoirs of Superfluid Helium coupled together and describe the quantum oscillations that result from varying the coupling strength. We explain the principles behind SHeQUIDs that can be built based on these oscillations and review some techniques and applications.

Jie Zhang - One of the best experts on this subject based on the ideXlab platform.

  • communication electron diffraction of ferrocene in Superfluid Helium droplets
    Journal of Chemical Physics, 2016
    Co-Authors: Jie Zhang, Yunteng He, Wei Kong
    Abstract:

    We report electron diffraction of ferrocene doped in Superfluid Helium droplets. By taking advantage of the velocity slip in our pulsed droplet beam using a pulsed electron gun, and by doping with a high concentration of ferrocene delivered via a pulsed valve, we can obtain high quality diffraction images from singly doped droplets. Under the optimal doping conditions, 80% of the droplets sampled in the electron beam are doped with just one ferrocene molecule. Extension of this size selection method to dopant clusters has also been demonstrated. However, incomplete separation of dopant clusters might require deconvolution and modeling of the doping process. This method can be used for studies of nucleation processes in Superfluid Helium droplets.

  • electron diffraction of Superfluid Helium droplets
    Journal of Physical Chemistry Letters, 2014
    Co-Authors: Jie Zhang, Yunteng He, William M Freund, Wei Kong
    Abstract:

    We present experimental results of electron diffraction of Superfluid Helium droplets and droplets doped with phthalocyanine gallium chloride and discuss the possibility of performing the same experiment with a laser aligned sample. The diffraction profile of pure droplets demonstrates dependence on the nozzle temperature, that is, on the average size of the droplets. Larger clusters demonstrate faster decay with increasing momentum transfer, whereas smaller clusters converge to isolated gas phase molecules at source temperatures of 18 K and higher. Electron diffraction of doped droplets shows similar modified molecular scattering intensity as that of the corresponding gas phase molecules. On the basis of fittings of the scattering profile, the number of remaining Helium atoms of the doped droplets is estimated to be on the order of hundreds. This result offers guidance in assessing the possibility of electron diffraction from laser aligned molecules doped in Superfluid Helium droplets.

Alkwin Slenczka - One of the best experts on this subject based on the ideXlab platform.

  • Electronic Spectroscopy of Phthalocyanine and Porphyrin Derivatives in Superfluid Helium Nanodroplets
    Molecules, 2017
    Co-Authors: Alkwin Slenczka
    Abstract:

    Phthalocyanine and porphyrin were among the first organic compounds investigated by means of electronic spectroscopy in Superfluid Helium nanodroplets. Superfluid Helium nanodroplets serve as a very gentle host system for preparing cold and isolated molecules. The uniqueness of Helium nanodroplets is with respect to the Superfluid phase which warrants the vanishing viscosity and, thus, minimal perturbation of the dopant species at a temperature as low as 0.37 K. These are ideal conditions for the study of molecular spectra in order to analyze structures as well as dynamic processes. Besides the investigation of the dopant species itself, molecular spectroscopy in Helium droplets provides information on the Helium droplet and in particular on microsolvation. This article, as part of a special issue on phthalocyanines and porphyrins, reviews electronic spectroscopy of phthalocyanine and porphyrin compounds in Superfluid Helium nanodroplets. In addition to the wide variety of medical as well as technical and synthetical aspects, this article discusses electronic spectroscopy of phthalocyanines and porphyrins in Helium droplets in order to learn about both the dopant and the Helium environment.

  • Microsolvation of anthracene inside Superfluid Helium nanodroplets
    Molecular Physics, 2012
    Co-Authors: Dominik Pentlehner, Alkwin Slenczka
    Abstract:

    This article reports on the microsolvation of anthracene in Superfluid Helium nanodroplets as revealed by electronic spectroscopy. Among the polyacene molecules benzene, naphthalene, anthracene, tetracene and pentacene only anthracene and tetracene have been found to exhibit multiplet splitting of the electronic and vibronic transitions which can not be explained by a rotational fine structure. The experimental approach for the investigation of the multiplet is the combined investigation of the fluorescence excitation spectrum and dispersed emission spectra. New experimental data are presented on the microsolvation of anthracene in Helium droplets. A detailed analysis of the anthracene data will be contrasted to corresponding data on tetracene. These data together with those reported for benzene, naphthalene and pentacene might serve to test and develop theoretical models which are needed to understand microsolvation of single molecules in Superfluid Helium droplets.

  • spectroscopic investigation of the solvation of organic molecules in Superfluid Helium droplets
    Journal of Chemical Physics, 2005
    Co-Authors: Rudolf Lehnig, Alkwin Slenczka
    Abstract:

    The spectroscopy of molecules doped into Superfluid Helium nanodroplets provides valuable information on the process of solvation in Superfluid Helium. In continuation of an earlier report on emission spectra of various phthalocyanines showing a splitting of all molecular transitions in the range of about 5–12cm−1, the emission spectra of tetracene, pentacene, and perylene in Superfluid Helium droplets are presented. The new spectra and the results obtained for the phthalocyanines are explained by an empirical model which accounts for the existence of different metastable configurations of a nonSuperfluid solvation layer around the guest molecule.