Interaction between Experiments, Analytical Theories, and Computation

This article is a summary of a talk given at the ACS Centennial Symposium in Physical Chemistry in Philadelphia in 2008, updated with more recent studies. In keeping with the spirit of the symposium, the article is in part historical and in part a review of the newer research. The talk was divided into two parts, the first on different isotopic effects in chemistry, including the mass-independent fractionation phenomenon in gases and H/D isotope effects in enzymes, and the second on two different surface phenomena, "The Bad and the Good". The "Bad" is the fluorescence intermittency of semiconductor nanoparticles, (quantum dots, QD) being an unwanted feature in sensor applications. The "Good" is the "on water" catalysis of organic reactions, a mode of green chemistry. The possible role of Auger-type mechanisms in trapping and detrapping in the QD and hence in the formation of dark and light periods is explored. Some suggestions are made on the novel "breakpoint" phenomenon discovered for H transfer in a thermophilic enzyme.