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This chapter discusses the specific properties of excitations in microcavities with crystalline as well as with amorphous organics. For organic microcavities, it is typical that the very large Rabi (of order of 100 meV) splitting has a strong influence on the temperature stability of organic cavity polaritons spectra. The coexistance of coherent and incoherent (localized) states of polaritons for microcavities with disordered organics is demonstrated. The dependence of polariton spectra on values of Davydov and Rabi splittings is calculated for microcavity with crystalline organics. The coexistance of localized and coherent states of cavity polaritons is demonstrated by numerical simulations that consider the model of 1D microcavity with diagonal disorder. For such a model, the comparison of the dynamics of low-energy wave packet in perfect and in disordered microcavity is performed.

This chapter presents the properties of thermal neutrons. Their wavelength (from the de Broglie equation) is well suited to the investigation of condensed matter, i.e., to the study of liquids, glasses (amorphous materials), and crystalline materials with varying degrees of order. That the neutrons carry magnetic moment also makes them well suited to the study of magnetic ordering. The theory of nuclear and magnetic scattering from individual atoms and from assemblies of atoms is presented, this leading to the definition of neutron scattering length and to the concepts of coherent and incoherent scattering. The focus then shifts to the direction and intensity of diffraction from crystalline materials (Bragg's law, structure factors), and to the description of this scattering when samples are presented in polycrystalline or powder form (Debye-Scherrer cones).

This chapter presents the so-called dielectric theory of the Frenkel excitons. The theory is the generalization of the local field Lorentz theory to the case of anisotropic molecular solids. It takes into account the local field corrections which determine the difference between lthe ocal and mean (Maxwell) electromagnetic field and allow for the calculation of the dielectric tensor for anisotropic crystals. The theory is applied to perfect and also to mixed crystalline solutions and crystals with impurities. It is shown how not only the transition dipoles but also the higher multipoles can be taken into account.

Polar and axial vectors and tensors are defined in terms of their behaviour under coordinate transformations. The effect of the time-reversal operator on kets and matrix elements is considered, followed by a tabulation of the space and time properties of various tensors — mechanical, electromagnetic, isotropic, and multipole. An account is given of the point-group symmetries of molecules and non-magnetic and magnetic crystals, with worked examples of the effect of symmetry on the components of a property tensor. The origin dependence of multipole moment operators is derived and used to obtain that of polarizability tensors up to electric octopole-magnetic quadrupole order. A pictorial approach is described for determining the symmetry conditions for the existence of an equilibrium effect and this is illustrated for the Faraday effect in a fluid and crystal.

This chapter discusses molecule formations. Topics covered include assemblages formed by atoms, the crystalline state, order-disorder transitions, gradual transitions, types of solid lattice, and properties of solids.

In this chapter, the formation, structures, and properties of a series of thermoplastic starch/ poly(vinylalcohol)(PVOH) nanocomposites with layered silicates are discussed. The relative concentrations of PVOH and layered silicate could be related to changes in intergallery spacing and formed a highly ordered intercalated structure. Dispersion of clay platelets was shown to be important in improving mechanical properties in these nanocomposites as was the interfacial interactions of filler and matrix (the more agglomerated composites containing both layered silicate and PVOH led to enhanced tensile strength and tensile modulus as compared to the more well dispersed composites without PVOH). Fourier transform infrared (FTIR) spectra of the thermoplastic starch and starch nanocomposites indicated a range of hydrogen bonding environments were produced between starch chains, PVOH and layered silicates during the extrusion processing stage. The evolution of distinct crystalline phases with ageing is also discussed.

This chapter explores how optics evolved as a science between roughly 350 BC and 160 AD according to three different, but roughly complementary, approaches. The first of these, the so-called philosophical approach, is exemplified in Aristotle’s account of visual perception, which was based on a range of psychological faculties from common sense, through imagination, to intellect. The second approach, which is epitomized in Euclid’s Optics and Catoptrics, was based on a geometrical analysis of sight according to visual rays. Its primary aim was therefore to account for spatial perception. The final approach, which is represented par excellence by Galen, looked to ocular anatomy and physiology for the explanatory basis of visual perception.

This chapter delves into the crystalline state – the one occupying the top position in the hierarchy of the phases of matter. A look at elastic scattering with a consideration of the crystalline state gives rise to diffraction patterns with very sharp and clearly defined structure. As such, it is the field in which the earliest X-ray scattering experiments were conducted. Their inherently repetitive nature is the feature that endows crystalline materials with long-range order. In the chapter's analysis, the conclusion that the scattering from a crystalline sample is non-zero only at sharp well-defined points in Q is arrived at with the convolution theorem. The scattering from an ideal crystalline sample can be non-zero only for very specific values of Q; these isolated points of scattered intensity are known as Bragg peaks.

This chapter posits that more severe types of crystal imperfections exist, and they are responsible for most of the physical properties of solids. It briefly describes mechanisms and/or organizations characterising those large variety of substances that progressively depart from the ideal crystalline state and approach the amorphous state. Particularly, the following are examined: crystalline twins, diffuse scattering, modulated structures, quasi-crystals, liquid crystals or mesomorphic phases, the paracrystal concept, amorphous and liquid states, and gases. Any crystal imperfection necessarily involves the violation of the perfect periodicity of the crystal. Different types of ordering can then arise, for which the basic definitions are provided here.

This chapter discusses the experimental methods used to study the diffraction of X-rays and neutrons by crystalline materials. Although electrons are also diffracted by crystals, electron diffraction is not discussed in any detail here. The chapter begins by describing how X-rays and neutrons are produced and how one can define the beam of radiation that will interact with the crystalline sample. The specimens that receive attention are single crystals and polycrystalline materials, the latter being ensembles of a large number of small single crystals or aggregates of small coherently scattering crystalline domains. The chapter proceeds by discussing in separate sections methods used to record diffraction patterns and to measure quantitatively the intensity of radiation scattered by these two types of specimen.

This chapter illustrates crystalline substances that are based on infinite arrays of atoms, where strong bonds are ubiquitous and not confined to molecules, namely, to neutral groups of atoms that can be stable in different states of the matter. The 2010 release of the Inorganic Crystal Structure Database reports 132,000 inorganic structures; also, because of the wide research of new materials, this number continuously increases, not to say of the number of inorganic compounds whose crystal structure is unknown. In past times most of the known inorganic compounds had their mineral counterpart. This, together with a historical paternity on crystallography, justifies a mineral name for most of the reference structure types. The term ‘inorganic structure’ has been applied to classes of compounds only in recent times.

This chapter discusses the physics of ultracold atoms trapped in optical lattices, i.e., ordered arrays of microscopic traps produced by the interference of counterpropagating laser beams. The motion of the atoms in these ‘crystals of light’ can be described in terms of a periodic potential, similar to the one experienced by the electrons of an ideal crystalline solid. The chapter focuses on the physics of quantum transport in optical lattices, which both provides a testing ground for ideal solid-state physics and constitutes an important resource for the determination of fundamental constants (e.g., the fine structure constant) and for the use of ultracold atoms as very precise sensors of forces (e.g., gravity).

The flow and deformation behaviours of soft matter are usually between those of fluids and elastic materials. For example, bubblegum can be stretched indefinitely like a fluid, but snaps back like an elastic material if a stretched piece is cut by scissors. The science that studies the flow and deformation of such complex materials is called rheology. Rheology is important in soft matter since many applications of soft matter rely on their unique rheological properties. This chapter discusses the rheological properties of polymeric materials (polymer solutions, melts, and cross-linked polymers). It covers the methods of macroscopic characterization of rheological properties of materials; and the molecular origins of the unique rheological properties of polymeric materials for polymer solutions, polymer melts, and liquid crystalline polymers.

The French Alps are the western part of the 1,200-km-long Alpine range extending eastward to the Vienna basin. They have the highest summits of the range, in the Mont-Blanc massif (4,807 m a.s.l.). In France, the chain has an arcuate form, convex to the north and west. It lies between Lake Geneva (46° 25′ N) and the Mediterranean coast (approximately 43° 35′ N). The Rhône valley forms a clear geological and morphological western limit. To the north (towards the Jura range) and the south-west (towards the ridges of Provence) the boundary is not so well defined. The French Alps and Alpine forelands have been thoroughly studied for over a century by many researchers from the Universities of Grenoble, Lyons, Aix-en-Provence, Nice, and Chambéry. First, it is necessary to outline the great diversity of landforms in relationship to the complex geological history, tectonics, and lithology. The importance of the Alpine karst landforms and caves must be emphasized; studies of these forms have been extended substantially in the last twenty years and they give many new insights into the Plio-Pleistocene tectonics and climates of this region. The past and present role of glaciers is another important topic in this chapter. From recent studies, we now have a much better knowledge of the transition from the last glacial period to the Holocene. It was impossible to write a chapter on the Alps and ignore the fact that the inhabitants of the Alps have to cope with many permanent natural hazards. The chapter ends with a short synthesis of the main morphogenic systems, which characterize the French Alps and forelands. In the north, the climate is oceanic and precipitation is evenly distributed throughout the year. A high relief, with landforms oriented transverse to the general western atmospheric circulation, results in a great variety of regional climates: from west to east, the continental effect is marked by a decreasing precipitation at the same altitude. Exposure and altitude combine to create contrasting local climates. Temperature inversion is frequent, especially when cold air is trapped in deep valleys.

There are two basic approaches for using solar energy to generate electricity. The first type, solar photovoltaic (PV) energy, uses semiconductors to convert sunlight into electricity. Crystalline silicon semiconductors are the most common type in use. The second approach is called concentrating solar power (CSP), also referred to as solar thermal. Basically, CSP uses mirrors to concentrate sunlight and generate steam, which is used to power a turbine. The most common method employed commercially is the parabolic trough, where the mirrors are horizontally disposed in a parabolic shape. Solar PV is more commonly used commercially because of high capital costs for building a CSP power plant. Solar PV has experienced rapid growth over the last ten years, increasing by more than twentyfold in the United States. Growth for CSP has increased threefold over the same ten years, but no growth over the last four years. Spain and the United States lead the world in commercial CSP plants.