论文标题
第一原理对尖端增强的拉曼散射的模拟揭示了底物在高分辨率图像上的主动作用
First-Principles Simulations of Tip Enhanced Raman Scattering Reveal Active Role of Substrate on High-Resolution Images
论文作者
论文摘要
尖端增强的拉曼散射（TERS）已成为获得原子运动的亚纳米空间分辨率指纹的强大工具。可以模拟拉曼散射过程并提供明确解释TERS图像的理论计算通常依赖于当地电场的粗近似值。在这项工作中，我们提出了一种基于新颖的原理方法，以结合时间依赖性密度功能理论（TD-DFT）和密度功能扰动理论（DFPT）来计算TERS图像，以将拉曼横截面与现实的本地领域计算。我们介绍了苯和TCNE分子的结果，后者在Ag（110）上被吸附。我们证明了化学作用对化学吸附分子的影响，在中等大小系统大小的模拟中通常被忽略，从而极大地改变了TERS图像。这要求将化学效应纳入预测理论实验的比较和对纳米级分子运动的理解。
Tip-enhanced Raman scattering (TERS) has emerged as a powerful tool to obtain subnanometer spatial resolution fingerprints of atomic motion. Theoretical calculations that can simulate the Raman scattering process and provide an unambiguous interpretation of TERS images often rely on crude approximations of the local electric field. In this work, we present a novel and first principles-based method to compute TERS images by combining Time-Dependent Density Functional Theory (TD-DFT) and Density Functional Perturbation Theory (DFPT) to calculate Raman cross sections with realistic local fields. We present TERS results on the benzene and TCNE molecule, the latter of which is adsorbed at Ag(110). We demonstrate that chemical effects on chemisorbed molecules, often ignored in TERS simulations of medium and large systems sizes, dramatically change TERS images. This calls for the inclusion of chemical effects for predictive theory-experiment comparisons and understanding of molecular motion at the nanoscale.
