First Encounter with Physical Chemistry

INTRODUCTION TO THE FIRST ENCOUNTER WITH PHYSICAL CHEMISTRY  

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INTRODUCTION TO THE "FIRST ENCOUNTER WITH PHYSICAL CHEMISTRY"... 

My first encounter with the field of colloid science occurred during my undergraduate studies, when I worked in a project on the electroacoustic zeta-potential measurement of colloidal suspensions. I probably did not understand much of the measurement technique, but I became fascinated with colloids for several reasons. First, they behave strangely —at least for a student of process engineering whose education in physics stopped right after mechanics and thermodynamics. Second, in our library I found some of the historical papers by Smoluchowski and others, which impressed by their age and the clear and comprehensible explanation of the physical phenomena in colloidal suspensions. Further on, I felt attracted by the interrelation of physics, chemistry and engineering. Last but not least, there was this mystery that our curriculum completely ignored the subject of colloids. 

Electron-transfer reactions are a class in which diffusion control may be observed. If an electron-donor species D (reductant) is to react with an electron acceptor A (oxidant), they first form an encounter complex, within which the transfer occurs by tunneling at a rate chiefly determined by the height of the barrier between the donor s HOMO and the acceptor s LUMO, and its width, which is determined by the distance of closest approach. If the transfer rate constant is large, the rate-limiting step will be the formation of the encounter complex by diffusion. This picture is an oversimplification. The theory developed by R. A. Marcus, and independently by others, is described in most physical chemistry texts (e.g., Atkins and de Paula, 2010, pp. 856-861). 

We begin in this chapter with a review of certain background information. You have already encountered most of the concepts to be presented in basic chemistry and physics courses. Why, then, the need for a review First, from experience we... 

The 90th Edition of the CRC Handbook of Chemistry and Physics marks a milestone for this reference work, which first appeared in 1913. For almost a century the Handbook has been updated annually, except for a few wartime years, and has served several generations of R D professionals, engineers, and students. Its aim has always been to provide broad coverage of all types of physical science data commonly encountered by scientists and engineers, with as much depth as can be accommodated in a one-volume format. The data contained in the Handbook have been carefully selected by experts in each field quality control is a high priority and the sources are documented. The annual updates make it possible to add new and improved data in a timely fashion, and references to more detailed data sources have helped to establish the Handbook as the first place to look for physical and chemical data. 

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