钠原子团簇的碰撞动力学

采用紧密结合的分子动力学模型，对第一个满壳附近（ｎ＝８）钠原子团簇碰撞Ｎａｎ＋Ｎａｎ的动力学性质进行了系统性研究。对有限温度下的多次模拟事件，在各种碰撞参数与不同轰击能量时，双团簇（Ｎａｎ）２的稳定性进行了研究。并发现，当质心系单原子能量为０．０２５ｅＶ时，对中心碰撞，（Ｎａ８）２能够存在３０００ｆｓ，而对周边碰撞，（Ｎａ８）２能够存在１００００ｆｓ；不管对中心碰撞还是对周边碰撞，在较低的轰击能量下，这种暂态双团簇结构具有较长的寿命；在相同的单原子轰击能量和相同的碰撞参数，（Ｎａ８）２和（Ｎａ９）２的动力学寿命没有差别，只是（Ｎａ８）２比（Ｎａ９）２的温度更低。

ON SODIUM CLUSTER COLLISIONAL DYNAMICS

Based on the Tight-binding molecular dynamics simulations, the Na n Na n collision dynamics around the first closed shell ( n=8) is systematically studied. The stability of sodium cluster dimers (Na n) 2 is investigated for many events with random relative orientation at finite temperature, various impact parameters and incident energies. We find that (Na 8) 2 can exist during about 3000 fs in central collisions while they can exist up to about ten thousands fs in peripheral collisions with larger impact parameters in fusion mechanism at CM energy per atom E cm / n =0.0250 eV. We observe that the lower the incident energy, the longer the lifetime of the cluster dimers in both central and peripheral collisions. There is no apparent difference in the dynamical stability of (Na 8) 2 and (Na 9) 2 although (Na 8) 2 is slightly colder than (Na 9) 2 and for the same incident energy per atom and the same impact paramenter.