mers, suspensions, composites), validated in part by single-molecule mechanical measurements, will be crucial to the growth in this area.

How can we obtain direct information on the molecular details of a reaction path and harness this for the design of new processes? While femtosecond spectroscopy has made it possible to observe reactions on a short time scale, a major challenge is to devise ultrafast techniques, such as superfast electron diffraction, that will permit observation of the actual molecular structure of a transition state, not just its rate of passage. As a general goal, we want to be able to make moving pictures of the reactions themselves, observing all the intermediate states and the rates at which they interconvert. Such moving pictures can be generated even now, by computer simulation of the reaction; the problem is to determine whether those pictures are correct. Thus a second challenge is to interface with theoretical chemistry in getting the best possible calculations, and then devise experimental tests of the major theoretical predictions to see whether experiments confirm the correctness of the calculations.

Most mechanistic work has focused on chemical reactions in solution or extremely simple processes in the gas phase. There is increasing interest in reactions in solids or on solid surfaces, such as the surfaces of solid catalysts in contact with reacting gases. Some such catalysts act inside pores of defined size, such as those in zeolites. In these cases only certain molecules can penetrate the pores to get to the reactive surface, and they are held in defined positions when they react. In fact, the Mobil process for converting methanol to gasoline depends on zeolite-catalyzed reactions.

There is also increasing interest in reactions involving organometallic compounds, at the interface between organic and inorganic chemistry. Many such reactions are useful in synthesis, where the organometallic reagents can have important properties as catalysts. Many details of reaction mechanisms in organometallic chemistry are yet unclear; understanding these mechanisms will allow the development of improved catalysts.

Much work has been done to help understand how metal ions react or catalyze reactions in solution. Many enzymes also use bound metal ions to catalyze their reactions, and there is still need to understand how they work. When we do understand them in detail, we should be able to produce biomimetic catalysts for useful processes in manufacturing.

When molecules react thermally, at room temperature or on heating, they are in their lowest electronic states. However, when reactions occur on irradiation of the molecules with visible or ultraviolet light, the processes involve species in electronic excited states. Some of the details of such processes are known, but there is still much to do. Since photoexcitation is important in many areas— photosynthesis, photography, electronic displays, solar cells, cancer-causing ul-

Front Matter (R1-R14)

Executive Summary (1-10)

1 Introduction (11-15)

2 The Structures and Cultures of the Disciplines: The Common Chemical Bond (16-21)

3 Synthesis and Manufacturing: Creating and Exploiting New Substances and New Transformations (22-40)

4 Chemical and Physical Transformations (41-54)

5 Isolating, Identifying, Imaging, and Measuring Substances and Structures (55-70)

6 Chemical Theory and Computer Modeling: From Computational Chemistry to Process Systems Engineering (71-94)

7 The Interface with Biology and Medicine (95-122)

8 Materials by Design (123-147)

9 Atmospheric and Environmental Chemistry (148-159)

10 Energy: Providing for the Future (160-170)

11 National and Personal Security (171-179)

12 How To Achieve These Goals (180-194)

Appendix A: Biographical Sketches of Steering Committee Members (195-201)

Appendix B: Statement of Task (202-202)

Appendix C: Contributors (203-208)

Index (209-224)