Crystallite Size Dependence of Plasmon Energies in Polycrystalline Graphite Observed by Reflected Electron Energy Loss Spectroscopy

Abstract

A comprehensive analysis of gened relativistic spacetimes which admit a shearfree, irrotational and geodesic time-like coogruence is presented. The equations governing the models for a gened energy-momentum tensor are wrilten down. Coordinates in which the metric of such spacetimes takes on a simplified form are established. The general subwses of 'zero anisotropic stress', 'zero heat-flux vector' and 'two-component Ruids' are investigated. In particular, perfect-fluid Friedmann-Robertson-Walker models and spatially homogeneous models are discussed. Models with a variety of physically relevant energy-momentum tensors are considered. Anisowopic fluid models and viscous fluid models with heat conduction are examined. Also. models with B perfect Ruid plus a magnetic field or with pure radiation. and models with two non-collinw perfect fluids (satisfying a variety of physical conditions) are inwtigated. In particular. models with a (single) perfect Ruid which is tilting with respect to the shem-free, vorticity-free and acceleration-free time-like congruence are discussed.PACS numbers: 0420J. 9880H

On the nature of cracks and voids in nuclear graphite

“…The intensity was found to reduce by an average of 40% relative to the bulk, which indicates a reduction in the degree of π bonding. These results are in line with those from polycrystalline graphite in [36] where a correlation between π plasmon energy and relative intensity was also found; and with results from a graphitization series in [18] where EELS spectra from pre-graphitized material show a π plasmon intensity of ca. 50% of that in the graphitized product.…”

“…In all cases, the reduction in π plasmon energy was to ca. 5 ± 0.5eV suggesting a reduction in crystallinity and density possibly due to sub 10nm crystallite sizes [36]. The normalised intensity of the π plasmon peak was also measured; a π plasmon window from 4.5eV to 8eV and total intensity window from -3eV to 50eV were used.…”

High‐resolution AES study of Ar+‐irradiated graphite

“…As a result, it was observed that the work function increased with the dosage of Ar C in a certain range, and the plasmon and the C plasmon energies decreased by increasing the dosage above certain doses. The relationship between the plasmon energy and the relative peak intensity in Ar C -irradiated graphite, and comparison with our previous work, 5 were also discussed.…”

“…5 The relationship between the plasmon energies and the relative peak intensities for Ar C -irradiated graphite and polycrystalline graphite is plotted in Fig. 5.…”

“…In an earlier work, we used reflected electron energy-loss spectroscopy (REELS) and revealed a correlation between the crystallite size of polycrystalline graphite and its plasmon energies. 5 In another study on HOPG, An et al have investigated the surface structure change of HOPG irradiated by 0.5-1.0 keV Ar C at doses of <5 ð 10 11 ions cm 2 by scanning tunnelling microscopy (STM) and atomic force microscopy (AFM). 6 They observed small discrete hillocks on the Ar C -irradiated surfaces at which the height measured by STM is larger than that measured by AFM in tapping mode, and considered that the difference is due to the increase in the partial density of states (DOS) caused by lattice damage.…”