Melting of Size Selected Clusters and Nanocrystals

在这个由化学系物理化学项目资助的项目中，西北大学的Martin Jarrold将进行一项研究计划，以研究材料熔化时的变化，因为它的尺寸从宏观到微观尺度减小。 离子迁移率技术将被用来研究金属团簇离子在气相中的熔化。 使用这种方法，将感测在熔化时发生的团簇的体积或形状变化。 关于熔化潜热的信息将使用离子迁移池中的碰撞诱导解离来确定。 测量将进行各种金属和碱金属卤化物集群。 目前很少有实验数据是关于熔融材料的行为的变化，作为散装材料的尺寸收缩到纳米制度。 该研究项目将深入了解体积熔化和非常小尺寸系统（小于500个原子）中的类似行为之间的联系，并最终帮助解释如何制备纳米尺寸的颗粒。 正因为如此，它对将纳米结构的合成从一门艺术转变为一门科学具有意义，并将影响纳米技术的许多方面。

In this project funded by the Physical Chemistry Program of the Chemistry Division, Martin Jarrold of Northwestern University will pursue a program of research to examine the changes in the melting of a material as it decreases in size from a macroscopic to a microscopic scale. The ion-mobility technique will be used to study the melting of metallic cluster ions in the gas phase. Using this method the volume or shape change of a cluster that occurs upon melting will be sensed. Information about the latent heat of fusion will be determined using collision-induced dissociation in an ion mobility cell. Measurements will be performed for a variety of metal and alkali-halide clusters. Very little experimental data is currently available about the change in the behavior of melting materials as the size of the bulk material shrinks to the nanometer regime. This research project will provide insight into the connection between bulk melting and analogous behavior in very small-size systems (fewer than 500 atoms) and should ultimately help explain how to prepare nanometer-sized particles. As such it has implications for turning the synthesis of nanoscale structures from an art into a science and will affect many aspects of nanotechnology.