Fedorov A S, Visotin M A, Gerasimov V S, Polyutov S P, Avramov P A
International Research Center of Spectroscopy and Quantum Chemistry-IRC SQC, Siberian Federal University, Krasnoyarsk 660041, Russia.
Kyungpook National University, Daegu 41566, South Korea.
J Chem Phys. 2021 Feb 28;154(8):084123. doi: 10.1063/5.0040128.
Charge transfer plasmons (CTPs) that occur in different topology and dimensionality arrays of metallic nanoparticles (NPs) linked by narrow molecular bridges are studied. The occurrence of CTPs in such arrays is related to the ballistic motion of electrons in thin linkers with the conductivity that is purely imaginary, in contrast to the case of conventional CTPs, where metallic NPs are linked by thick bridges with the real optical conductivity caused by carrier scattering. An original hybrid model for describing the CTPs with such linkers has been further developed. For different NP arrays, either a general analytical expression or a numerical solution has been obtained for the CTP frequencies. It has been shown that the CTP frequencies lie in the IR spectral range and depend on both the linker conductivity and the system geometry. It is found that the electron currents of plasmon oscillations correspond to minor charge displacements of only few electrons. It has been established that the interaction of the CTPs with an external electromagnetic field strongly depends on the symmetry of the electron currents in the linkers, which, in turn, are fully governed by the symmetry of the investigated system. The extended model and the analytical expressions for the CTPs frequencies have been compared with the conventional finite difference time domain simulations. It is argued that applications of this novel type of plasmon may have wide ramifications in the area of chemical sensing.
研究了由窄分子桥连接的金属纳米颗粒（NP）不同拓扑结构和维度阵列中出现的电荷转移等离子体激元（CTP）。与传统CTP情况不同，在传统CTP中金属NP由具有由载流子散射引起的实光学电导率的厚桥连接，而在这种阵列中CTP的出现与具有纯虚电导率的薄连接体中电子的弹道运动有关。用于描述具有这种连接体的CTP的原始混合模型得到了进一步发展。对于不同的NP阵列，已经获得了CTP频率的一般解析表达式或数值解。结果表明，CTP频率位于红外光谱范围内，并且取决于连接体电导率和系统几何形状。发现等离子体激元振荡的电子电流仅对应于少数几个电子的微小电荷位移。已经确定，CTP与外部电磁场的相互作用强烈取决于连接体中电子电流的对称性，而电子电流的对称性又完全由所研究系统的对称性决定。将扩展模型和CTP频率的解析表达式与传统的时域有限差分模拟进行了比较。有人认为，这种新型等离子体激元的应用可能在化学传感领域产生广泛影响。
