Gas-Phase Cluster Dynamics: Clustering and Growth

Abstract

This chapter provides an overview of gas-phase cluster dynamics focusing on its clustering and growth. The ultimate objective of developing a detailed understanding of gas-phase cluster collisions is to enable the formulation and solution of quantitative kinetic descriptions of cluster formation and growth. The importance of gas-phase cluster formation and growth has already been established in both laboratory research and in industry but at present, the design of these processes is largely empirical. Thus, it is important to develop quantitative theoretical tools to guide the way for the development of new materials and processes through an understanding of their routes to synthesis. For ultrafine aerosol particles or equivalently for energetically highly stable clusters, approaches are now available for computing collision-coagulation rates that take composition into account. Stable clusters are either dominant from the outset of a process, or represent the limiting condition for a cluster system evolving toward energetic stability. Thus, these developments will be of considerable utility both for testing the evolutional kinetics of aerosols of energetically stable clusters and for describing the large-cluster limit of colliding small or marginally-stable clusters. For the small and relatively unstable clusters, a format is under development that should ultimately enable kinetic descriptions of both simple, monomer-dominated growth processes and more complex collisional evolution processes.