Transition state theory essential feature

Because the transition-state theory is essential for even a qualitative understanding of solvent effects on reaction rates, some important features of this theory are outlined below. 

The essential feature of transition state theory is that there is a concentration of the species at the saddle point, the transition state or activated complex, that is in equihbrium with reactants and products. The Boltzmann Distribution Law governs the concentration of that transition state, and the rate of reaction is proportional to its concentration. Since the concentration... 

Photoelectron spectroscopy has confirmed the essential features of the MO description of bonding in simple molecules however, the proper MOs are not always easy to visualize. A localized bond representation, involving hybrid AOs which overlap little with each other, accounts for most of the chemically important properties of most molecules and the localized bonds are easy to visualize. The localized bond picture can be related to the proper (approximate) description through perturbation theory. The localized bond model is generally not applicable to electron-deficient molecules, conjugated systems, or transition states. The application of perturbation theory to the description of these three cases where the localized bond model breaks down is the subject of the following chapters. 

Each view of the bonding of NO to copper predicts that dd features in the visible and near-IR regions of the absorption and MCD spectra of the nitrosyl complexes will be absent, an hypothesis that was supported by experiment. The MLCT assignment for the 500 nm optical absorption band is also consistent with the bonding pictures, because the filled, essentially d orbital set prohibits an alternative LMCT attribution. A metal d r NO transition to yield an essentially Cu(II)-(NO ) excited state seems reasonable—and is predicted by ab initio theory (53)—... 

At this point, we had the first four of the seven characteristic features of A-B-A thermoplastic elastomers, as shown in the box. That is, we were completely confident that we had a three-block polymer, rubbery behavior with high tensile strength in the unvulcanized state, and also complete solubility. We concluded from these properties that these polymers were two-phase systems. We then generated the essentials of the two-phase, domain theory and visualized the physical structure illustrated schematically in Figure 1. We also visualized applications in footwear, in injection-molded items, and in solution-based adhesives. Positive confirmation of the two-phase structure quickly followed, by detection of two separate glass transition temperatures, as well as observation of the thermoplasticlike reversibility of bulk- and... 

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