Density and temperature dependence of the momentum distribution in liquid helium 4

Journal Article · Fri Dec 01 04:00:00 EST 1995 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00754515· OSTI ID:175465

Snow, W M ^[1]; Sokol, P E ^[2]

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1. Argonne National Lab., IL (United States)
2. Pennsylvania State Univ., University Park, PA (United States)

Deep inelastic neutron scattering measurements on liquid {sup 4}He have been carried out for temperatures from 0.35 K to 4.2 K and densities from 0.125 to 0.200 g/cm{sup 3} at a momentum transfer of 23 {angstrom}{sup -1}. These measurements are at large enough momentum transfer that deviations from the Impulse Approximation are accurately described by current theories and information on the single particle momentum distribution may be extracted from the measured scattering. The scattering exhibits non-Gausian behavior in both the normal liquid and superfluid phases. A distinct change in the scattering, marked by a reduction in the width and increased deviations from the classical Gaussian shape, occurs at the superfluid transition. We present a comparison of our experimental results with recent calculations at a variety of temperatures and densities and show that theory and experiment are in excellent agreement. We also present model scattering functions, obtained by correcting for instrumental resolution and final state effects, that represent the scattering in the IA limit. Finally, we present values for the average kinetic energy and the Bose condensate fraction over a broad range densities and temperatures.

• OSTI ID: 175465
• Journal Information: Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 5-6 Vol. 101; ISSN JLTPAC; ISSN 0022-2291
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
DEEP INELASTIC SCATTERING
HELIUM 4
KINETIC ENERGY
MOMENTUM TRANSFER
NEUTRON DIFFRACTION
SUPERFLUIDITY
TEMPERATURE DEPENDENCE