A variety of chemical systems exhibit multiple reaction pathways that adjoin to a common reactant state. In fact, any reaction producing side products or proceeding via a stable intermediate involves a species possessing at least two reaction pathways. Despite improvements in ab initio transition-state search algorithms it remains difficult to detect multiple reaction pathways. Typically, multi...

The Direction of a Reaction Suppose we have a reaction such as A + B ↔ C , which has come to equilibrium at some temperature τ . Now we raise the temperature. Does the equilibrium shift to the left (more A and B) or to the right (more C)? The heat of reaction at constant pressure, Qp, is the heat that must be supplied to the system if the reaction goes from left to right. If Qp > 0, heat is abs...

the doping reaction of truncated boron nitride and carbon nanotubes with aluminium atom wastheoretically investigated. the am1, pm3, and pm6 semiempirical methods have been used toevaluate the thermochemistry of doping reactions of single walled boron nitride nanotubes andcarbon nanotubes. the enthalpy changes, gibbs free energy changes, and entropy changes of studieddoping reactions were evalu...

A solution containing a reacting, autocatalytic and bistable chemical system can spontaneously form patterns and structure from erstwhile homogenous aqueous reaction solutions. Among some of the patterns formed are concentric rings and thermal plumes. The exothermic chemical reaction fuels the pattern-formation through a coupling of Marangoni and Rayleigh±BeÂnard-type thermogravitatioal effects...

ion of surface hydrogen by atomic H from graphane, diamond 001 , diamond 111 , and hydrogenated amorphous carbon a-C:H surfaces was studied using density-functional theory calculations in the generalized gradient approximation. Our calculations show that for each surface, the abstraction reaction is highly exothermic with a negligible activation energy barrier. The degree of exothermicity depen...

Polymethylmethacrylate-based (PMMA) bone cements containing functionalized carbon nanotubes (CNTs) were prepared, and the thermal properties of the resultant nanocomposite cements were characterized in accordance with the international standard for acrylic resin cements. The aim of this study was to determine the peak temperatures during the polymerization reaction in PMMA bone cement by thermo...

The kinetic theory for a fluid of hard spheres which undergo endothermic and/or exothermic reactions with mass transfer is developed. The exact balance equations for concentration, density, velocity, and temperature are derived. The Enskog approximation is discussed and used as the basis for the derivation, via the Chapman-Enskog procedure, of the Navier-Stokes reaction equations under various ...