Molecular-dynamics simulations are presented for the diffusion-controlled bimolecular reaction A+B<=>C in two and three dimensions.The reactants and solvent molecules are modeled as spheres interacting via continuous potential-energy functions.The interaction potential between two reactants contains a deep well that results in a reaction.When the solvent concentration is low and the reactant dynamics is essentially ballistic,the system reaches equilibrium rapidly,and the reaction follows classical kinetics with exponential decay to the equilibrium.When the solvent concentration is high the particles enter the normal diffusion regime quickly and nonclassical behavior is observed,i.e.,the reactant concentrations approach equilibrium as t~(-d/2) where d is the dimensionality of space.When the reaction well depth is large,however,the reaction becomes irreversible within the simulation time.In this case the reactant concentrations decay as t~(d/4).Interestingly this behavior is also observed at intermediate times for reversible reactions.
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机译：针对二维和三维扩散控制的双分子反应A + B = C进行了分子动力学模拟，将反应物和溶剂分子建模为通过连续势能函数相互作用的球体，两种反应物之间的相互作用势包含当溶剂浓度低并且反应物动力学本质上是弹道时，系统迅速达到平衡，反应遵循经典动力学，并且指数衰减至平衡。当溶剂浓度高时，颗粒迅速进入正常扩散状态，观察到非经典行为，即反应物浓度趋于平衡，为t〜（-d / 2），其中d为空间维数。当反应井深度较大时，反应变为不可逆在这种情况下，反应物的浓度衰减为t〜（d / 4），有趣的是这种现象也被观察到d在中间时间进行可逆反应。
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