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1997 (3)
1993 (1)
1Author    R. C. Blasdell, D. M. Ceperley, R. O. SimmonsRequires cookie*
 Title    Neutron and PIMC Determination of the Longitudinal Momentum Distribution of HCP, BCC and Normal Liquid 4 Het  
 Abstract    Deep inelastic neutron scattering has been used to measure the neutron Compton profile (NCP) of a series of condensed 4 He samples at densities from 28.8 atoms/nm 3 (essentially the minimum possible density in the solid phase) up to 39.8 atoms/nm 3 using a chopper spectrometer at the Argonne National Laboratory Intense Pulsed Neutron Source. At the lowest density, the NCP was measured along an isochore through the hep, bcc, and normal liquid phases. Average atomic kinetic energies are extracted from each of the data sets and are compared to both published and new path integral Monte-Carlo (PIMC) calculations as well as other theoretical predictions. In this prelimi-nary analysis of the data, account is taken of the effects of instrumental resolution, multiple scatter-ing, and final-state interactions. Both our measurements and the PIMC theory show that there are only small differences in the kinetic energy and longitudinal momentum distribution of isochoric helium samples, regardless of their phase or crystal structure. 
  Reference    Z. Naturforsch. 48a, 433—437 (1993); received December 27 1991 
  Published    1993 
  Keywords    Momentum distribution, Neutron, Helium 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0433.pdf 
 Identifier    ZNA-1993-48a-0433 
 Volume    48 
2Author    Ralf Schmidt, Christian Gebauer, Olaf Klein, Wolfhart SeidelRequires cookie*
 Title    Anisotropie Interaction Potentials for He-Pyrrole, He-Furane and He-Thiophene from total Differential Cross Section Measurements  
 Abstract    Differential cross section measurements are reported for scattering of an improved He-atomic beam by crossed beams of Pyrrole, Furane and Thiophene. The damping of the DCS diffraction oscillations is used to extract reliable anisotropic intermolecular potentials, applying the infinite order sudden approximation (IOSA). 
  Reference    Z. Naturforsch. 52a, 317—322 (1997); received September 19 1996 
  Published    1997 
  Keywords    Molecular Beams, Helium, Interaction Potentials, Aromaticity, Heterocyclic Compounds 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0317.pdf 
 Identifier    ZNA-1997-52a-0317 
 Volume    52 
3Author    Markus Hammer, Wolfhart SeidelRequires cookie*
 Title    Helium Atom Scattering from C 2 H 6 , F 2 HCCH 3 , F 3 CCH 2 F and C 2 F 6 in Crossed Molecular Beams  
 Abstract    Rotationally unresolved differential cross sections were measured in crossed molecular beam exper-iments by scattering Helium atoms from Ethane, 1,1-Difluoroethane, 1,1,1,2-Tetrafluoroethane and Hexafluoroethane. The damping of observed diffraction oscillations was used to extract anisotropic interaction potentials for these scattering systems applying the infinite order sudden approximation (IOSA). Binary macroscopic parameters such as second heterogeneous virial coefficients and the coefficients of diffusion and viscosity were computed from these potentials and compared to results from macroscopic experiments. 
  Reference    Z. Naturforsch. 52a, 695—701 (1997); received August 8 1997 
  Published    1997 
  Keywords    Molecular beams, Helium, Interaction potential, Fluoroethanes, Binary coefficients 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0695.pdf 
 Identifier    ZNA-1997-52a-0695 
 Volume    52 
4Author    Christian Gebauer, Olaf Klein, Ralf Schmidt, Wolfhart SeidelRequires cookie*
 Title    Helium Atom Scattering from Cyclopentane, Pyrrolidine and Tetrahydrofurane in Crossed Molecular Beams  
 Abstract    Scattering of helium atoms by cyclopentane, pyrrolidine and tetrahydrofurane molecules was ob-served in crossed molecular beam experiments. The intensity of scattered helium atoms, depending on the scattering angle, was measured with high resolution, and the damping of the diffraction oscil-lations of the differential cross sections was used to extract elastic anisotropic interaction potentials for these molecules. The evaluation included a geometric transformation concerning the puckered states of the envelope and the twisted conformation of the molecules. The potentials were found to be rather similar. 
  Reference    Z. Naturforsch. 52a, 425—431 (1997); received February 27 1997 
  Published    1997 
  Keywords    Molecular beams, helium, saturated 5-rings, interaction potentials, ring puckering 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0425.pdf 
 Identifier    ZNA-1997-52a-0425 
 Volume    52