tailieunhanh - Ideas of Quantum Chemistry P90

Ideas of Quantum Chemistry P90 shows how quantum mechanics is applied to chemistry to give it a theoretical foundation. The structure of the book (a TREE-form) emphasizes the logical relationships between various topics, facts and methods. It shows the reader which parts of the text are needed for understanding specific aspects of the subject matter. Interspersed throughout the text are short biographies of key scientists and their contributions to the development of the field. | 856 15. Information Processing - the Mission of Chemistry Fig. . A model of the immune system. a The figure shows schematically some monomers in a solvent. They have the shape of a slice of pie with two synthons protruding up and protruding down differing in shape. The monomers form some side-by-side aggregates containing from two to six monomers each aggregate resulting in some pattern of synthons on one face and the complementary pattern on the other face. We have then a library of all possible associates in thermodynamical equilibrium. Say there are plenty of monomers a smaller number of dimers even fewer trimers etc. up to a tiny concentration of hexamers. b The attacking factor I the irregular body shown is best recognized and bound by one of the hexamers. If the concentration of I is sufficiently high the equilibrium among the aggregates shifts towards the hexamer mentioned above which therefore binds all the molecules of I making them harmless. If the attacking factor was II and III binding could be accomplished with some trimers or dimers as well as some higher aggregates . The defence is highly specific and at the same time highly flexible adjustable . The immune system in our body is able to fight and win against practically any enemy irrespective of its shape and molecular properties charge distribution . How is it possible Would the organism be prepared for everything Well yes and no. Let us imagine a system of molecules building blocks having some synthons and able to create some van der Waals complexes Fig. . Since the van der Waals forces are quite weak the complexes are in dynamic equilibrium. All possible complexes are present in the solution none of the complexes dominates. Now let us introduce some enemy-molecules . The building blocks use part of their synthons for binding the enemies that have complementary synthons and at the same time bind among themselves in order to strengthen the interaction. Some of the complexes are especially .