Coherent Excitation of a He* Beam Observed in Atomic Momentum Distributions

1996 ◽  
Author(s):  
C. Kurtsiefer ◽  
C.R. Ekstrom ◽  
D. Voigt ◽  
O. Dross ◽  
T. Pfau ◽  
...  
Keyword(s):  
Coherent Excitation ◽  
Momentum Distributions ◽  
Atomic Momentum

Coherent excitation of a He∗ beam observed in atomic momentum distributions

1996 ◽  
Vol 123 (4-6) ◽  
pp. 505-511 ◽  
Author(s):  
Christopher R. Ekstrom ◽  
Christian Kurtsiefer ◽  
Dirk Voigt ◽  
Oliver Dross ◽  
Tilman Pfau ◽  
...  
Keyword(s):  
Coherent Excitation ◽  
Momentum Distributions ◽  
Atomic Momentum

Study of the anisotropy in the atomic momentum distributions in a Kapton film

2001 ◽  
Vol 13 (22) ◽  
pp. 5053-5063 ◽  
Author(s):  
D Nemirovsky ◽  
R Moreh ◽  
Y Finkelstein ◽  
J Mayers
Keyword(s):  
Momentum Distributions ◽  
Atomic Momentum

Deep Inelastic Neutron Scattering in the Study of Atomic Momentum Distributions

1993 ◽  
Vol 48 (1-2) ◽  
pp. 425-432 ◽  
Author(s):  
Alan C. Evans ◽  
Jerry Mayers ◽  
David N. Timms ◽  
Malcolm J. Cooper
Keyword(s):  
Inelastic Neutron Scattering ◽  
Impulse Approximation ◽  
Inelastic Neutron ◽  
Statistical Accuracy ◽  
Momentum Distributions ◽  
Atomic Momentum ◽  
Interpretive Method ◽  
Pulsed Neutron ◽  
Pulsed Neutron Source ◽  
Scattered Beam

Abstract The electron-volt spectrometer (EVS) at the pulsed neutron source facility (ISIS) is being developed for the study of atomic momentum distributions. Neutrons with energies in the range 1 to 100 eV are incident on the sample, and the time-of-flight (TOF) spectrum of the scattered beam is measured by an array of fixed detectors. A resonant foil difference technique is used to yield a set of TOF spectra for those neutrons scattered into a fixed energy and through fixed angles. Information on the momentum distribution of the target nuclei can be deduced within an impulse approximation in a procedure analogous to that in Compton scattering of electrons by photons.Crystalline compounds containing aligned hydrogen bonds and other hydrogenous compounds are of particular interest owing to the high cross-section of the proton at these neutron energies. With improved statistical accuracy of the data it is anticipated that deviations of the proton's potential from a harmonic potential may be determined. Non-hydrogenous systems have also been investigated. A description is given of the basic theory and interpretive method. Data obtained on numerous systems are presented and discussed.

Atomic momentum distributions in condensed matter

1985 ◽  
Vol 63 (1) ◽  
pp. 68-75 ◽  
Author(s):  
V. F. Sears
Keyword(s):  
Momentum Distribution ◽  
Inelastic Neutron Scattering ◽  
Condensed Matter ◽  
Inelastic Neutron ◽  
The Central Limit Theorem ◽  
Momentum Distribution Function ◽  
Momentum Distributions ◽  
Atomic Momentum ◽  
Zero Momentum ◽  
Anharmonic Crystals

The theory of the momentum distribution function for atoms in condensed matter is reviewed and compared with results of deep-inelastic neutron-scattering experiments. We discuss, in particular, the case of classical and almost-classical liquids, harmonic and anharmonic crystals, and solid and liquid 4He. Except for liquid 4He in the superfluid phase, the momentum distribution is always Gaussian to a good approximation. In some cases this Gaussian behavior is of dynamical origin while, in others, it is a consequence of the central-limit theorem. The observed momentum distribution in superfluid 4He provides direct experimental evidence for the macroscopic occupation of the zero-momentum state and the value of the condensate fraction can be obtained.

COHERENT EXCITATION AND EVOLUTION OF TWO-PHONON STATES IN MOLECULAR CRYSTALS

1985 ◽  
Vol 46 (C7) ◽  
pp. C7-281-C7-286
Author(s):  
F. Vallée ◽  
G. Gale ◽  
C. Flytzanis
Keyword(s):  
Molecular Crystals ◽  
Coherent Excitation
Sign in / Sign up

Export Citation Format

Share Document