Effect of separation on second-order hyperpolarizability of two silver nanoclusters

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• 作者：Ying Chang ; Weiqi Li ; Yongyuan Jiang ; ^{jiangyy@hit.edu.cn}
• 关键词：Silver nanoclusters ; Hyperpolarizability ; Molecular orbital
• 刊名：Physics Letters A
• 出版年：2012
• 出版时间：9 July, 2012
• 年：2012
• 卷：376
• 期：34
• 页码：2314-2318
• 全文大小：424 K

文摘

We present a study on dielectric response of Ag₁₄ nanocluster dimer using first principles methods. The interaction energy, (hyper)polarizability of dimer are predicted under various separations of the two identical Ag₁₄ nanoclusters. The appropriate separation makes the second-order hyperpolarizability of Ag₁₄ dimer is about 70 times larger than the Ag₁₄ monomer. The increase of polarizability and hyperpolarizability is ascribed to reconfiguration of molecular electronic state from Ag cluster monomer to dimer. Nonlinear response is more susceptible to the steady intermediate state compared to linear response. The crucial transitions contributed to hyperpolarizability are assigned to be from highest occupied molecular orbitals to the lowest unoccupied molecular orbital (HOMOs-LUMO) of nanocluster dimer. Binding character of LUMO plays an important role in determining nonlinear optical properties.