【摘要】 利用紧束缚分子动力学方法研究了硅团簇Sin(n =5— 10 )的熔化行为 .给出了团簇熔化潜热和熔点随团簇尺寸的变化关系 ,表明团簇熔化潜热和熔点强烈依赖于团簇的原子数 .计算结果表明硅团簇熔化机理与金属团簇熔化有很大不同 ,金属小团簇的熔化是一个从低温类固态向高温类固态转变的过程 ,在转变温区 ,类固态和类液态处于动力学共存 ,而硅团簇在转变温区则是处于一种中间态 ,这种中间态既不是类固态又不是类液态 .比较了用不同计算方法和定义方法所得硅团簇熔点 .更多还原

【Abstract】 The Tight-binding molecular-dynamics(TBMD) has been used to study the melting behaviour of small silicon clusters Si n(n=5—10). We report the calculated results of the latent heat of fusion Δμ ls and the melting temperature T m as a function of cluster size. Δμ ls and T m exhibit a strong dependence on cluster size. The melting mechanisms of silicon clusters are distinguished from metal clusters. The melting of metal clusters can be described as a transition from a low-energy solid-like structure at low temperatures to a higher-energy liquid-like structure at high temperatures. At the transition temperature, metal clusters undergo a dynamics coexistence of the two states, while the silicon clusters undergo an intermediate state which is neither liquid-like structure nor solid-like structure. The melting points obtained by using different calculation methods and definitions also have been compared in this work.更多还原