Observation of Ballistic Rotons in Liquid 4He

  • D. O. Edwards
  • G. G. Ihas
  • C. P. Tam


The excitations produced when a pulsed 4He atomic beam strikes the surface of liquid 4He held near T ~ OK have been measured as a function of direction in the liquid and time elapsed since the beam was generated. Comparison of the data with a theory which assumes that a single atom is converted into a single excitation indicates that the observed signals are due to ballistic phonons and rotons, although the experimental velocity and angular distributions of the excitations are displaced from the theoretical ones. The direction of the displacements suggests that multiple ripplon production occurs as an atom approaches the liquid surface, as predicted by Echenique and Pendry.


Angular Distribution Transverse Momentum Atomic Beam Single Atom Maxwellian Velocity Distribution 
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Copyright information

© Plenum Press, New York 1977

Authors and Affiliations

  • D. O. Edwards
    • 1
  • G. G. Ihas
    • 1
  • C. P. Tam
    • 1
  1. 1.Physics DepartmentThe Ohio State UniversityColumbusUSA

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