Acceptor-donor reaction theory

Application of the Reaction Path Hamiltonian Method to the Reaction H2 + OH —> H2O + H Acceptor-Donor (AD) Theory of Chemical Reactims (O 4)... 

A more general theory of acids and bases was devised independently by Johannes Br0n sted (Denmark) and Thomas M Lowry (England) m 1923 In the Brpnsted-Lowry approach an acid is a proton donor, and a base is a proton acceptor The reaction that occurs between an acid and a base is proton transfer... 

At the microscopic level, acids are defined as proton (H ) donors (Bronsted-Lowry theory) or electron-pair acceptors (Lewis theory). Bases are defined as proton (H+) acceptors (Bronsted-Lowry theory) or electron-pair donors (Lewis theory). Consider the gas-phase reaction between hydrogen chloride and ammonia ... 

In a metal, the Fermi level is located within the conduction band. In a semiconductor, this level usually is found in the forbidden gap between the valence band and the conductivity band by doping it can be shifted up or down relative to the band edges. The activation energy of a catalyzed reaction depends on the distance of the Fermi level from the band edges for acceptor reactions it is related to the distance from the conduction band, for donor reactions to the distance from the valence band. The exact theory will not be presented here it has been given by Hauffe (6) and by Steinbach (9). 

Markoffian theories for luminescence of solids. For fluid systems a kinetic theory of excitation transfer between donor and acceptors, where reaction probability is modulated by translational diffusions, has been submitted to numerical analysis. ... 

In the third part (acceptor-donor theory of chemical reactions), we will find the answer to the question of where the reaction barrier comes from and what happens to the electronic structure when the reaction proceeds. 

Maybe the acceptor-donor theory described above pertains only to the H - - H-H reaction Fortunately, its applicability goes far beyond that. Let us consider a nucleophilic attack 5n2 of the H ion on the ethylene molecule (Fig. 14.18), perpendicular to the ethylene plane toward the position of one of the carbon atoms. The arriving ion binds to the carbon atom forming the CH bond, while another proton with two electrons (i.e., H ion) leaves the system. Such a reaction looks like it has only academic interest (except some isotopic molecules are involved, e.g.. 

In the acceptor-donor theory at the intermediate stage of the reaction (I),... 

H3N -f Ba3 H3NBCl3 in which NH3 is the base (donor) and BCI3 the acid (acceptor). The Lewis theory establishes a relationship between acid-base reactions and oxidation-reduction reactions. See HSAB principle. See also aqua aod hy-droxoacid oxoacid. 

As we have seen, for computational reasons we are able to take into account only reactions involving a few nuclei. However, chemists are interested in the reactivity of much larger molecules. We would like to know what particular features of the electronic structure make a chemical reaction proceed. This is the type of question that will be answered in the acceptor-donor theory. "... 

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