Deviations from the impulse approximation in liquid sup 4 He: Momentum-transfer dependence

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.44.308· OSTI ID:5748021

Herwig, K W; Sokol, P E ^[1]; Snow, W M; Blasdell, R C ^[2]

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1. Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802 (US)
2. Materials Science Division and Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, Illinois 60439 (US)

We have carried out a series of deep-inelastic-neutron-scattering (DINS) measurements on liquid {sup 4}He to study the {ital Q} dependence of deviations from the impulse approximation, called final-state effects (FSE). DINS measurements on liquid {sup 4}He have been carried out for temperatures of 0.75 and 4.25 K at a density of 0.147 g/cm{sup 3} for momentum transfers between 10 and 23 A {sup {minus}1}. Under the assumption that current theoretical calculations of the momentum distribution of liquid {sup 4}He are accurate, we extract the form of FSE in the superfluid phase from the scattering data. We find that FSE are definitely present in the scattering data, and their effects are more important at lower {ital Q}'s. We also compare the predictions of several theories for FSE to the experimental data. We find that the recent theories of FSE of Silver and of Carraro and Koonin are in excellent agreement with the data in the superfluid phase at {ital Q}=23 A {sup {minus}1}. At the lower values of {ital Q}, deviations from these theories appear. No current theory describes the observed FSE completely at the lower {ital Q}'s.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5748021
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 44:1; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
COHERENT SCATTERING
DIFFRACTION
EVEN-EVEN NUCLEI
FINAL-STATE INTERACTIONS
FLUIDS
HELIUM 4
HELIUM ISOTOPES
IMPULSE APPROXIMATION
INELASTIC SCATTERING
INTERACTIONS
ISOTOPES
LIGHT NUCLEI
LIQUIDS
MOMENTUM TRANSFER
NEUTRON DIFFRACTION
NUCLEI
SCATTERING
STABLE ISOTOPES
ULTRALOW TEMPERATURE