Shock-Compression Processes in Solid State Chemistry

Shock-Compression Processes in Solid State Chemistry 

In this chapter The background of shock-induced solid-state ehemistry eonceptual models and mathematical models chemical reactions in shock-compressed porous powders sample preservation. 

It is indeed a distressing prospect to contemplate the complications introduced by chemical changes into an otherwise orderly physical description. The chemical complications are intimately intertwined with the mechanical and physical effects, which are already understood to be more complex than present theory indicates. As the questions addressed in solid state chemistry are quite different from those addressed in prior work, new approaches are required to develop a scientific understanding of the field. 

Solid state chemistry is controlled by defects, and the highly defective, shock-compressed solid provides the optimal condition for chemical change. 

142 Chapter 6. Shock-Compression Processes in Solid State Chemistry 

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The present book, with contributions from a group of very knowledgable scientists in the field, is an attempt to provide a basis for addressing Bridgman s concerns. The response requires multidisciplinary contributions from solid mechanics, solid-state physics, materials science, and solid-state chemistry. Certainly, advances in theory, experimentation, and numerical simulation are impressive, and many aspects of shock-compressed solids have been studied in detail. At the fundamental level, however, it is certainly appropriate to question how well shock-compression processes are understood. 

Shock-compressed solids and shock-compression processes have been described in this book from a perspective of solid state physics and solid state chemistry. This viewpoint has been developed independently from the traditional emphasis on mechanical deformation as determined from measurements of shock and particle velocities, or from time-resolved wave profiles. The physical and chemical studies show that the mechanical descriptions provide an overly restrictive basis for identifying and quantifying shock processes in solids. These equations of state or strength investigations are certainly necessary to the description of shock-compressed matter, and are of great value, but they are not sufficient to develop a fundamental understanding of the processes. 

Shock-induced solid state chemistry represents the most complex fundamental problem ever encountered in shock-compression science. All the mechanical and physical complications of other work are present, yet the additional chemical complications are added. Indeed, all mechanical, physical, and chemical aspects of the problem are intimately intertwined. Chemical investigations promise to provide a description of shock compression that differs considerably from that to which we have become accustomed. Nevertheless, a full description of the process requires contributions from a number... 

Certainly the ability to carry out chemical reactions at pressures of tens of GPa in times of a microsecond or less provides an opportunity to explore chemistry under extreme conditions as described by the report. Nevertheless, the conditions under which chemical reactions proceed under high pressure shock compression are complex and not well understood, and careful, systematic investigations are required to develop the ability to control and predict the reactions. The particular emphasis of work reported in this chapter is to study the solid state aspects of such processes. 

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