Measurement of anisotropies of the kinetic energy and anharmonicity in pyrolytic graphite by neutron Compton scattering

Fielding, Andrew; Timms, D N; Mayers, J.

doi:10.1209/epl/i1998-00465-1

Cited by 32 publications

(24 citation statements)

References 30 publications

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“…Vos et al [14] noticed the universality of the angle dependence of the recoil effect in graphite observed in large angle electron scattering [15], neutron scattering [16] and HAXPES [4]. In scattering experiments, the direction of momentum transferq can be controlled by choosing the events between the transmission configuration (hereq is parallel to the graphite plane) and reflection configuration (q [4] is perpendicular to the plane) by tilting the HOPG samples for a fixed scattering angle.…”

Section: ð8:13þmentioning

confidence: 99%

“…Meanwhile, Fig. 8.3c contains the data for neutron scattering [16] for transmission (open circles) and reflection (filled squares). Despite the differences in the physical processes underlying these three experiments, the similarity of their spectral features is startling.…”

Section: ð8:13þmentioning

confidence: 99%

“…Actually, all three sets of experimental data are well fitted by the anisotropic Debye model without any adjustable parameters. In the neutron scattering experiment performed by Fielding et al [16], the value of the momentum transfer (23.4 a.u.) is very similar to that for the photoemission experiment [4] (23.8 a.u.).…”

Section: ð8:13þmentioning

confidence: 99%

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Recoil Effects in X-ray Photoelectron Spectroscopy

Kayanuma

2015

Springer Series in Surface Sciences

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Recent advances in hard X-ray photoelectron spectroscopy (HAXPES) have made it possible to measure electronic energy levels with resolution as high as 80 meV for photon energies extending to as high as 10 keV. For such high energy photoelectrons, the recoil momentum imparted to the atoms is no longer negligible, even though the momentum of the incident photon can safely be neglected. Here, the recoil effects in HAXPES of solids as well as gas-phase molecules are reviewed. It is shown that by comparison of the experimental data with quantum mechanical theories based on appropriate models of matter, information on the local environments of the emitter atoms in the material is obtained. IntroductionThe foundation of the principles of photoelectron spectroscopy can be traced back to the celebrated article of Einstein in 1905 [1], in which the kinetic energy E kin of a photoelectron is given by the conservation law of energy aswhere hm is the incident photon energy and W is the binding energy with respect to the vacuum level. Although this is one of the simplest equations to appear in the literature, it has the unequaled power of enabling us to determine the binding energy of the electrons in materials by subtraction of two observable quantities, hm and E kin .

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Section: ð8:13þmentioning

confidence: 99%

Section: ð8:13þmentioning

confidence: 99%

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Recoil Effects in X-ray Photoelectron Spectroscopy

Kayanuma

2015

Springer Series in Surface Sciences

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“…The final energy of the neutron is fixed by passing the scattered beam through a resonance gold absorber whose peak energy is 4.912 eV and a half width at half maximum of 133 meV which limits the instrumental resolution of the system. From the difference between the measured TOF spectra with and without the Au resonance absorber, the momentum distribution of the scattering atom is obtained as described in detail in [22]. Apart from water, other samples such as graphite and diamond were studied by both techniques.…”

Section: The Ncs Techniquementioning

confidence: 99%

Comparison between electron and neutron Compton scattering studies

Moreh

Finkelstein

Vos

2015

EPJ Web of Conferences

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Abstract. We compare two techniques: Electron Compton Scattering (ECS) and neutron Compton scattering (NCS) and show that using certain incident energies, both can measure the atomic kinetic energy of atoms in molecules and solids. The information obtained is related to the Doppler broadening of nuclear levels and is very useful for deducing the widths of excited levels in many nuclei in self absorption measurements. A comparison between the atomic kinetic energies measured by the two methods on the same samples is made. Some results are also compared with calculated atomic kinetic energies obtained using the harmonic approximation where the vibrational frequencies were taken from IR/Raman optical measurements. The advantages of the ECS method are emphasized.

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“…Deviations from the IA, possibly present at the finite momentum transfer of the neutron scattering experimental set-up, are known as Final State Effects (FSE). These effects appear as an asymmetry in the experimental response function and a shift in the peak position [13,16].…”

Section: Introductionmentioning

confidence: 99%

Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

Andreani

Colognesi

Degiorgi

et al. 2003

Nuclear Instruments and Methods in Physics Research Section A:

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The principles of the Double Difference (DD) method, applied to the neutron spectrometer VESUVIO, are discussed. VESUVIO, an inverse geometry spectrometer operating at the ISIS pulsed neutron source in the eV energy region, has been specifically designed to measure the single particle dynamical properties in condensed matter. The width of the nuclear resonance of the absorbing filter, used for the neutron energy analysis, provides the most important contribution to the energy resolution of the inverse geometry instruments. In this paper, the DD method, which is based on a linear combination of two measurements recorded with filter foils of the same resonance material but of different thickness, is shown to improve significantly the instrumental energy resolution, as compared with the Single Difference (SD) method. The asymptotic response functions, derived through Monte-Carlo simulations for polycrystalline Pb and ZrH 2 samples, are analysed in both DD and SD methods, and compared with the experimental ones for Pb sample. The response functions have been modelled for two distinct experimental configurations of the VESUVIO spectrometer, employing 6 Li-glass neutron detectors and NaI g detectors revealing the g-ray cascade from the ðn; gÞ reaction, respectively. The DD method appears to be an effective experimental procedure for Deep Inelastic Neutron Scattering measurements on VESUVIO spectrometer, since it reduces the experimental resolution of the instrument in both 6 Li-glass neutron detector and g detector configurations.

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Measurement of anisotropies of the kinetic energy and anharmonicity in pyrolytic graphite by neutron Compton scattering

Cited by 32 publications

References 30 publications

Recoil Effects in X-ray Photoelectron Spectroscopy

Recoil Effects in X-ray Photoelectron Spectroscopy

Comparison between electron and neutron Compton scattering studies

Double difference method in deep inelastic neutron scattering on the VESUVIO spectrometer

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