气相中原子分子成簇动力学Ⅰ.动力学的基本模型

Atomic and Molecular Clustering Kinetics in Gas Phase Ⅰ. Basic Model of Chemical Kinetics

提出了气相原子、分子碰撞形成团簇的动力学一般模型，认为具有特定组份单元的粒子经碰撞后可任意组合成团簇．各缔合速率常数随团簇的尺寸和结构特征而变化．团簇的热解离速率主要取决于断键数．因此裂解出小碎片的几率较大．将上述模型用动力学方程表示，可计算在不同时刻的团簇尺寸分布．最后分析了激光烧蚀、电弧放电等几种形成团簇方法的具体条件．

A general model is suggested for the kinetics of clustering processes. It isconsidered that cluster species are composed of units of specific composition. Arbitrarycombinations occur between the species. The association rate constant depends on thecluster size and the structural feature. The dissociation rate constant mainly depend onthe number of bonds broken during dissociation. Thus the small fragments are easier tobe cleavaged. The master equations for the kinetic model are given. They can be used forthe numercial calculation of the cluster distribution at various time. Finally, the clusteringprocesses during laser ablation and arc discharge are discussed.