Emergence of a Low-Energy Peak in the Smoothed Absolute Value Circular Dichroism Spectra of Small Helical Gold Nanorods
Emergence of a Low-Energy Peak in the Smoothed Absolute Value Circular Dichroism Spectra of Small Helical Gold Nanorods
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DOI：
10.1021/acsomega.3c04943
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发表时间：
2024-01
期刊：
影响因子：
4.1
通讯作者：
Harold P. Hodgins;Jonathan J. Foley;Alexander O. Govorov;Stephen K. Gray;Ian P. Hamilton
中科院分区：
文献类型：
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作者：
Harold P. Hodgins;Jonathan J. Foley;Alexander O. Govorov;Stephen K. Gray;Ian P. Hamilton
我们计算，使用含时密度泛函理论，吸收和圆二色性（CD）光谱的一系列小螺旋金纳米棒结构的宽度为0.6 nm和长度增加从0.7 nm的Au24到1.9 nm的Au56。对于一个低能量的窗口，从1.7到4.1 eV，加宽的吸收光谱中的线的结果在一个低的能量峰，以前的研究已经确定为（本地化）等离子体共振。正如预期的那样，等离子体共振的吸收峰位置随着纳米棒长度的增加而系统地红移。然而，CD和直接加宽的CD光谱的趋势更难以辨别。我们介绍的绝对值CD光谱的想法，并表明，拓宽线的结果在一个低能量峰，以前没有报道。随着纳米棒长度的增加，峰位系统性红移，但范围明显小于吸收光谱的范围。
We calculate, using time-dependent density functional theory, absorption and circular dichroism (CD) spectra for a series of small helical gold nanorod structures with a width of 0.6 nm and length increasing from 0.7 nm for Au24 to 1.9 nm for Au56. For a low-energy window, ranging from 1.7 to 4.1 eV, broadening the lines in the absorption spectra results in a low energy peak which previous studies have identified as the (localized) plasmon resonance. As expected, the absorption peak position of the plasmon resonance systematically redshifts as the length of the nanorod increases. However, trends in the CD and straightforwardly broadened CD spectra are more difficult to discern. We introduce the idea of an absolute value CD spectrum and show that broadening the lines results in a low energy peak that has not previously been reported. The peak position systematically redshifts as the length of the nanorod increases but over a significantly smaller range than that for the absorption spectrum.