Time-Dependent Density Functional Theory Studies of Optical Properties of Ag Nanoparticles: Octahedra, Truncated Octahedra, and Icosahedra
Time-Dependent Density Functional Theory Studies of Optical Properties of Ag Nanoparticles: Octahedra, Truncated Octahedra, and Icosahedra
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DOI：
10.1021/jp300789x
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发表时间：
2012-05-10
影响因子：
3.7
通讯作者：
Aikens, Christine M.
中科院分区：
文献类型：
--
作者：
Bae, Gyun-Tack;Aikens, Christine M.
理论上研究了银纳米粒子的大小和形状对其光吸收性能的影响，以了解这些体系的等离子体性质。用含时密度泛函理论(TDDFT)计算了一系列银团簇(Ag-n，n=6-85)在不同电荷状态下的光学吸收光谱，这些电荷状态分别为八面体、截断八面体和二十面体。计算了n=6、19、44、85的八面体Ag-n团簇，n=13、38、55、79的截断八面体Ag-n团簇，以及n=13、43、55的二十面体Ag-n团簇。荷电系统被认为是获得闭壳电子结构的系统。计算采用ADF程序，优化采用BP86/DZ理论水平，激发计算采用SAOP泛函和LB94泛函。尖锐的激发峰来自轨道跃迁的混合物，而广泛的激发来自八面体、截断的八面体和二十面体的Ag-n团簇中的多个激发态。我们预测，随着团簇变大，最大吸收峰红移，随着团簇形状从八面体变为二十面体，最大吸收峰蓝移。
The effect of the size and shape of silver nanoparticles on their optical absorption properties is theoretically investigated to understand the plasmonic properties of these systems. Time-dependent density functional theory (TDDFT) calculations are employed to calculate the optical absorption spectra for a series of silver clusters (Ag-n, n = 6-85) in various charge states whose structures are octahedral, truncated octahedral, and icosahedral. Octahedral Ag-n clusters with n = 6, 19, 44, 85, truncated octahedral Ag-n clusters with n = 13, 38, 55, 79, and icosahedral Ag-n clusters with n = 13, 43, 55 are calculated. Charged systems are considered to obtain closed shell electronic structures. These calculations are performed with the ADF code with the BP86/DZ level of theory in the optimizations and the SAOP functional and LB94 functional in the excitation calculations. A sharp excitation peak originates from a mixture of orbital transitions, and a broad excitation arises from multiple excited states in octahedral, truncated octahedral, and icosahedral Ag-n clusters. We predict that the absorption peak maximum red shifts as the cluster becomes larger and blue shifts as the shape of clusters changed from octahedral to icosahedral.