Progress in the following studies is reported: optical properties; Raman and inelastic neutron scattering; hydrogen storage in alkali metal-graphite intercalation compounds (GIC's); intercalation chemistry of the MX/sub 5/-graphite intercalation compounds (M = As, Sb, X = Cl, F); and low-temperature magnetoresistance (acceptor-GIC's) and pressure-dependent superconductivity (donor GIC's). The objective of the optical reflectance measurements is to determine the frequency dependent dielectric constant for several important graphite intercalation compounds and to correlate this constant with theoretical predictions. Our recent Raman scattering work has primarily focused on the intercalation-induced shifts of zone-center, zone-interior and zone-edge graphitic, phonon frequencies in prototypical acceptor (SbCl/sub 5/-graphite) and donor (Rb-graphite) cmpounds. The inelastic neutron scattering work has focused on the low energy (.omega.

Optical spectroscopy (Raman, FTIR and Reflection) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

The research on graphite intercalation compounds often acts as a forerunner for research in other sciences. For instance, the concept of staging, which is fundamental to graphite intercalation compounds, is also relevant to surface science in connection with adsorbates on metal surfaces and to high-temperature superconducting oxide layer materials. Phonon-folding and mode-splitting effects are not only basic to graphite intercalation compounds but also to polytypical systems such as supercon ductors, superlattices, and metal and semiconductor superlattices. Charge transfer effects playa tremendously important role in many areas, and they can be most easily and fundamentally studied with intercalated graphite. This list could be augmented with many more examples. The important message, however, is that graphite inter calation compounds represent a class of materials that not only can be used for testing a variety of condensed-matter concepts, but also stimulates new ideas and approaches. This volume is the second of a two-volume set. The first volume addressed the structural and dynamical aspects of graphite intercalation compounds, together with the chemistry and intercalation of new compounds. This second volume provides an up-to-date status report from expert researchers on the transport, magnetic, elec tronic and optical properties ofthis unique class of materials. The band-structure cal culations of the various donor and acceptor compounds are discussed in depth, and detailed reviews are provided ofthe experimental verification ofthe electronic struc ture in terms of their photoemission spectra and optical properties.

The progress of materials science depends on the development of novel materials and the development of novel experimental techniques. The research on graphite intercalation compounds combines both aspects: new compounds with strikingly new and anisotropic properties have been synthesized and analyzed during the past couple of years by means of state-of-the-art experimental methods. At the same time, the preparation of the compounds already known has improved con siderably, giving increased reliability and reproducibility of the experimental results. The high quality experimental data now available have stimulated theo retical work. Moreover, the theoretical work has had a great impact on further experimental studies, with the effect of a much improved understanding of this class of materials. This volume is dedicated to a thorough description of all relevant experimen tal and theoretical aspects of the structural and dynamical properties of graphite intercalation compounds. Because of the large number of topics, a second vol ume, which is now in preparation, will follow and will treat the electronic, transport, magnetic, and optical properties. The second volume will also contain a chapter on applications of graphite intercalation compounds. There have been a number of reviews written on selected aspects of these compounds in various journals and conference proceedings during the last couple of years, but this is the first comprehensive review since the thorough overview provided by M.S. Dresselhaus and G. Dresselhaus appeared ten years ago.

This book covers the basic physics and chemistry of graphite intercalation compounds. Emphasis is laid on the layered or quasi-two-dimensional structure of these compounds, which provides an exciting arena for testing physical concepts in lower dimensions. The chapters in this volume, all of which have been written by internationally recognized experts in the field, cover the following topics: the structure and phase transitions of intercalate atoms and molecules in graphite, the physics of staging formation and staging transitions, the lattice dynamics of these compounds as determined by inelastic neutron scattering and optical methods, the diffusivity of the guest species, mesoscopic properties such as domain structures and stacking arrangements, and the synthesis of new compounds. The reviews provide a comprehensive overview of the current status of the field of two- dimensional physics.

Graphite intercalation compounds are a new class of electronic materials that are classified as graphite-based host guest systems. They have specific structural features based on the alternating stacking of graphite and guest intercalate sheets. The electronic structures show two-dimensional metallic properties with a large variety of features including superconductivity. They are also interesting from the point of two-dimensional magnetic systems. This book presents the synthesis, crystal structures, phase transitions, lattice dynamics, electronic structures, electron transport properties, magnetic properties, surface phenomena, and applications of graphite intercalation compounds. The applications covered include batteries, highly conductive graphite fibers, exfoliated graphite and intercalated fullerenes and nanotubes.

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

The research on graphite intercalation compounds often acts as a forerunner for research in other sciences. For instance, the concept of staging, which is fundamental to graphite intercalation compounds, is also relevant to surface science in connection with adsorbates on metal surfaces and to high-temperature superconducting oxide layer materials. Phonon-folding and mode-splitting effects are not only basic to graphite intercalation compounds but also to polytypical systems such as supercon ductors, superlattices, and metal and semiconductor superlattices. Charge transfer effects playa tremendously important role in many areas, and they can be most easily and fundamentally studied with intercalated graphite. This list could be augmented with many more examples. The important message, however, is that graphite inter calation compounds represent a class of materials that not only can be used for testing a variety of condensed-matter concepts, but also stimulates new ideas and approaches. This volume is the second of a two-volume set. The first volume addressed the structural and dynamical aspects of graphite intercalation compounds, together with the chemistry and intercalation of new compounds. This second volume provides an up-to-date status report from expert researchers on the transport, magnetic, elec tronic and optical properties ofthis unique class of materials. The band-structure cal culations of the various donor and acceptor compounds are discussed in depth, and detailed reviews are provided ofthe experimental verification ofthe electronic struc ture in terms of their photoemission spectra and optical properties.