Acceleration of Cosmic Rays to Energies above 1015 eV by Transrelativistic Shocks

Journal of Experimental and Theoretical Physics - MHD flows with transrelativistic 4-velocities Γβ ~ 1, which are realized in Ib/c-type supernovae and after the coalescence of neutron...     

Intramolecular reorganization 2. The Brønsted correlation for a series of gas-phase reactions of deprotonation of <Emphasis Type="Italic">para</Emphasis>-substituted toluene derivatives with the CH<Subscript>2</Subscript>CN<Superscript>−</Superscript> anion

A proton-transfer model proposed earlier that includes equalization of energies of the reactant and product by an intramolecular mechanism was used to study gas-phase reactions of deprotonation of para-substituted toluene derivatives (substituents were NH₂, OH, CH₃, H, Cl, NC, CN, and NO₂) with the CH₂CN^? anion. The energy parameters of the reactions were determined from ab initio calculations. The Brønsted correlation based on the results obtained was analyzed in the framework of conventional quantum chemical formalism (the Marcus equation). The problem of disbalance of the changes in the geometry of the activated complex relative to its position on the reaction coordinate was considered taking some geometric parameters of the system as examples.     

Intramolecular reorganization 1. Deprotonation of toluene with the CH<Subscript>2</Subscript>CN<Superscript>−</Superscript> anion: an analysis in the framework of a gas-phase model

A mechanism is proposed of intramolecular reorganization leading to equalization of the energies of reactants and products in a nonequilibrium proton transfer reaction. The model proposed allows one to extend a conventional quantum chemical treatment to gas-phase proton transfer. Taking the reaction of toluene deprotonation with the CH₂CN⁻ anion (a conjugate base of acetonitrile) as an example, it was shown that the activation energy and its components can be determined from direct ab initio calculations. The effect of disbalance of structural changes relative to the “equilibrium” proton transfer is considered. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1808–1815, September, 2008.