具有排斥相互作用的原子团簇非平衡系统研究

在无格点基底表面建立了存在排斥相互作用的原子团簇凝聚及扩散模型，对沉积在均匀带电硅油基底表面的银原子凝聚过程进行了研究.结果表明：当沉积原子凝聚成稳定的原子团簇后，由于带同种电荷，团簇之间存在库仑排斥作用，团簇数密度随时间呈指数形式衰减，衰减时间常数为Oa_a；两团簇相互离散的相对平均速率V与它们之间的相对距离L在 统计意义上成正比，即V=HL.停止沉积后初期,H≈Oa_a，然后随着扩散时间的增 加，H逐渐趋于零；随着液体基底黏滞系数增加，摩擦力增大，H逐渐减小，摩 关键词： 排斥相互作用 团簇 扩散

Studies on a nonequilibrium atomic cluster system with repulsive interactions

A simulation model for diffusion and aggregation of atomic clusters with repulsi ve interactions on nonlattice substrates is established, and the aggregation pro cess of the silver atoms on charged silicone oil surfaces has been studied. It w as found that after the stable atomic clusters form, due to the repulsive intera ction among the clusters, the number density of the atomic clusters decays with time exponentially and the time constant is Oa_a; statistically, the relative speed V between two clusters increases linearly with their distance L according to V=HL, where the constant H≈Oa_a after deposition and then approaches zero with time. With the increase of the viscosity coefficient o f liquid substrates, the friction force increases and H decreases. A linear relation between the friction force and H is found with the slope k≈0 10±001 We show that the critical radius r1₁ of the clusters, abo ve which the atomic clusters start to carry charges, is related nearly to the at omic affinity, i.e., the energy needed for the cluster to carry an extra electro n. It is found that H and Oa_a increase slowly with r1₁ and their slopes are 12±03s-1^-1μm-1^-1 and 16±06s-1^{-1μm-1-1, respectively. Our simulation results are in agreement w ith the previous experimental findings.}