Atomic Momentum Distribution of Solid 4He Henry Glyde, University of Delaware, Oscar Vilches, Univer

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Atomic Momentum Distribution of Solid 4HeHenry
Glyde, University of Delaware, Oscar Vilches,
University of Washington,John Larese, University
of Tennessee Focused Research Group, Neutron
Scattering DMR-0115663

• In classical solids, liquids and
• gases, the atomic momentum
• distribution, n(k), is always the
• Gaussian, Maxwell-Boltzmann
• distribution. Using neutron
• Compton scattering methods we
• show that shape of n(k) in the
• highly quantum, highly
• anharmonic solid 4He differs
• markedly from a Gaussian. There
• is high occupation of low
• momentum states (see opposite) in
• this cold quantum solid. (Phys. Rev.
• Lett. (submitted) (2004))

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Atomic Momentum Distribution
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Atomic Momentum distribution in Solid 4He Henry
Glyde, University of Delaware, Oscar Vilches,
University of Washington, John Larese,
University of Tennessee Focused Research Group,
Neutron Scattering DMR-0115663
The atomic momentum distribution was measured by
Souleymane Omar Diallo and Richard T. Azuah on
the MARI instrument at the ISIS Neutron Facility,
U.K. An educational goal is to train young
scientists in neutron scattering techniques in
preparation for the Spallation Neutron Source
coming on line At Oak Ridge National Lab. Shown
opposite is Richard (top) instructing students
and Souleymane (bottom) attending a neutron
summer school at NIST, Gaithersburg.