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Title: Noble-Gas Nanoclusters with Fivefold Symmetry Stabilized in Superfluid Helium

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930667
Report Number(s):
BNL-81162-2008-JA
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98
Country of Publication:
United States
Language:
English
Subject:
national synchrotron light source

Citation Formats

Kiryukhin,V., Bernard, E., Khmelenko, V., Boltnev, R., Krainyukova, N., and Lee, D. Noble-Gas Nanoclusters with Fivefold Symmetry Stabilized in Superfluid Helium. United States: N. p., 2007. Web. doi:10.1103/PhysRevLett.98.195506.
Kiryukhin,V., Bernard, E., Khmelenko, V., Boltnev, R., Krainyukova, N., & Lee, D. Noble-Gas Nanoclusters with Fivefold Symmetry Stabilized in Superfluid Helium. United States. doi:10.1103/PhysRevLett.98.195506.
Kiryukhin,V., Bernard, E., Khmelenko, V., Boltnev, R., Krainyukova, N., and Lee, D. Mon . "Noble-Gas Nanoclusters with Fivefold Symmetry Stabilized in Superfluid Helium". United States. doi:10.1103/PhysRevLett.98.195506.
@article{osti_930667,
title = {Noble-Gas Nanoclusters with Fivefold Symmetry Stabilized in Superfluid Helium},
author = {Kiryukhin,V. and Bernard, E. and Khmelenko, V. and Boltnev, R. and Krainyukova, N. and Lee, D.},
abstractNote = {},
doi = {10.1103/PhysRevLett.98.195506},
journal = {Physical Review Letters},
number = ,
volume = 98,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Macroscopic samples (volume{approx}cm{sup 3}, atomic density{approx}10{sup 19}-10{sup 20} cm{sup -3}) of noble-gas nanoclusters (size{approx}5-6 nm) were produced in superfluid helium by an impurity-helium gas injection technique. X-ray diffraction measurements show that the samples consist of weakly interacting nanoclusters with fivefold symmetry, such as icosahedra and decahedra. These results open new opportunities for fundamental research of nanoclusters of noble gases and other materials in well-controlled environments using experimental techniques requiring bulk samples.
  • Concentrations of H and D atoms, stabilized in a molecular matrix, up to 1 x 10/sup 20/ cm/sup -3/ are achieved by condensation of an atomic beam in superfluid helium. Transformation of D atoms into H atoms is observed, indicating the occurrence of tunneling chemical exchange reactions between atomic and molecular hydrogen isotopes.
  • We have conducted an ultrasonic pulse-time-of-flight investigation of the squashing mode of superfluid {sup 3}He-{ital B} in a magnetic field. All five of the expected Zeeman sublevels for this {ital J}=2{sup {minus}} mode were observed. The investigation was done at a very low temperature ({ital T}/{ital T}{sub {ital c}}{lt}0.35) to reduce the quasiparticle broadening that tends to smear the collective modes and makes resolution of the individual sublevels impossible. Variation of the pressure was used to sweep the collective-mode frequencies through the operating frequency, 137.6 MHz of the resonant-sound transducers. Both group-velocity spectroscopy and pulse-shape analysis were used for identificationmore » of different sublevels. Performing experiments at different orientations of the sound propagation with respect to magnetic-field direction (parallel, perpendicular, 55{degree}, and 13{degree}) was the key to observation of all five modes and their identification. The Lande {ital g} factor was obtained from the linear dependence of the {ital J}{sub {ital z}}=+2 sublevel on magnetic field and compared with theory.« less
  • The ring reorientation in permethylferrocene has been studied by using high-resolution solid-state /sup 13/C NMR. The constraints which symmetry places upon the number and types of motional parameters which may be determined from the NMR spectrum are discussed. From comparison of the experimental line shapes in the slow reorientation temperature range with theoretical models for random rotations and symmetry-related jumps, it is concluded that the reorientation occurs as jumps between symmetry-related orientations with jumps of 2..pi../5 highly favored over 4..pi../5. The activation energy derived for the jump process is 13.5 kJ/mol.
  • The presence of a monoclinic {tau}{sup 2}-Al{sub 13}Co{sub 4} phase, whose a and c are about {tau}{sup 2} = 2.618 ({tau} = (1 + {radical} 5)/2) times greater than the respective parameters of the monoclinic Al{sub 13}Co{sub 4}, and its (100) and (001) twins has been reported earlier. Like its prototype structure, the monoclinic Al{sub 13}Fe{sub 4}/Al{sub 13}Co{sub 4}, this {tau}{sup 2}-Al{sub 13}Co{sub 4} also shows a tendency to form multiple twins displaying five-fold symmetry. A transmission electron microscopic study of the twin mechanisms has been carried out. In addition to the well-known (001) and (100) glide twins, (20-1) glidemore » twins have also been found. Alternate (100)-(20-1) or (100)-(001)-(100) twinning will yield twins displaying, five-fold symmetry. The distribution of Co atoms in the pentagonal layer in {tau}{sup 2}-Al{sub 13}Co{sub 4} and the tessellation of pentagons in the tessellation of pentagons in the (100) and (20-1) glide twins have also been studied by high-resolution electron microscopy.« less