考虑一个由两种类粒子组成的系统,同种类粒子相遇时发生不可逆的聚集反应;不同种类的粒子相遇时,则发生不可逆的完全湮没反应.利用Mont-Carlo模拟各种参数条件下的粒子聚集-完全湮没竞争过程,分析了聚集速率、湮没速率以及初始浓度分布对系统动力学行为的影响.模拟结果表明:1)粒子大小分布总是满足一定的标度律;2)当两种粒子的聚集速率都等于湮没速率的2倍时,粒子大小分布的标度指数与粒子初始浓度分布有关;3)其余情况下,标度指数则取决于反应速率的相对大小.此外,当两种粒子的聚集速率都大于或等于湮没速率的两倍,系统的所有粒子将完全湮没;当且仅当至少一种粒子的聚集速率小于湮没速率的两倍,聚集速率较小的那一种粒子才可能最终保存下来.模拟结果与已报道的理论分析结果符合得较好.
A two-species system is considered, in which irreversible aggregations occur between particles of the same species while irreversible complete annihilations occur between particles of different species. Such competing processes between aggregation and annihilation reactions are performed by Monte Carlo simulations under various parameter conditions, and the influences of aggregation rate, annihilation rate, and initial particle distribution on the dynamics of the system are analyzed in detail. Simulation results indicate that the particle size distributions always obey a certain scaling law. When the aggregation rates of the two kinds of particles are both twice as fast as the annihilation rate, the scaling exponents of the particle size distributions have relation with the initial particle distribution; while in the remaining cases, the scaling exponents depend crucially on the reaction rates. Moreover, when both aggregation rates are larger than or equal to the double of the annihilation rate, all particles will annihilate each other completely; while at least one of the aggregation rates is slower than the double of the annihilation rate, the species with slower aggregation rate could survive finally. Simulation results are in good agreement with the reported theoretical solutions.