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The lowest energy structures of (SiO2)nO2 duster skeletons with size from n = 2 to 12 is investigated theoretically by genetic algorithm. The calculations based on the Tsuneyuki-Tsukada Aoki Matsui (TTAM) and Flikkema- Bromley (FB) potentials give the same result: n = 4 and n = 8 are the magic numbers in the virtual (SiO2)nO2 cluster sequence. This conclusion is in agreement with the experimental observation on the [(SiO2)nO2H3]- cluster sequence. The comparison of the present results with those from the density-functional-theory calculations on (SiO2)nO2H4 shows that addition of II atoms to the O terminals of (SiO2)nO2 clusters to form the complex (SiO2)nO2H4 clusters has only minor influence on the relative energies and the structures of different isomers. This means that the magic behaviour of the dusters [(SiO2)nO2H3]^- (n=4,8) observed in our previous experiment is originated from the stability of the cluster skeletons (SiO2)nO2 (n = 4, 8) . 相似文献
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TIME DECAY BEHAVIOR OF FULLERENE-C60 STUDIED BY TIME-RESOLVED PHOTOLUMINESCENCE 总被引:1,自引:0,他引:1 下载免费PDF全文
The time-resoved photoluminescence spectra of C60 have been studied from toluence solution at room temperature and from thin film at both room temperature and 77K. A photoluminescence peak at about 730nm was detected from solution at room temperature and film at 77K, in which lifetimes waz determined to be 1.1 and 0.9ns, respectively. At room temperature, the photoluminescence peak of thin film shifted to 740 nm with fast decay behavior which was fitted well to a double-exponential lifetimes with τ1 = 0.087ns, τ2= 0.68 ns. Two relaxation mechanisms are given tentatively in explaining this phenomenon. 相似文献
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采用一种第一性原理多体势来描述团簇Ben中原子之间的相互作用,用模拟自然界生物进化的方法系统地优化计算了Ben团簇(n=2-55)的基态能量和几何结构,分析了其拓扑性质,总结了能量和结构随原子数目的变化规律,并将得到的Ben的结果和长程Morse势所描述的金属团簇Mn,以及LennardJones势所描述的惰性气体团簇LJn进行了比较 相似文献
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模拟生物进化的机理,建立了优化团簇结构的理论程序,并对Si和Be团簇结构进行了优化计算。并成功地得到了用其它方法已发现的团簇基态结构,还发现了用其它方法尚未得到的团簇基态结构;所得到的团簇基态能量等于或小于已发表的用其它方法所得到的相应团簇的基态能量,说明此方法对于优化团簇基态结构是可行和有效的。 相似文献
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