Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 58: Poster Wednesday: New Methods and Developments, Frontiers of Electronic Structure Theory

O 58.1: Poster

Wednesday, September 7, 2022, 18:00–20:00, P4

Fully Atomistic Modelling of Tip-enhanced Raman Spectra from First Principles — •Yair Litman, Franco Bonafe, Alaa Akkoush, Heiko Appel, and Mariana Rossi — MPI for the Structure and Dynamics of Matter, Hamburg, Germany.

Tip-enhanced Raman scattering (TERS) has emerged as a powerful tool to study surfaces with subnanometer spatial resolution [1]. In particular, single-molecule TERS studies have shown the capability to visualize high-resolution images of individual molecular normal modes in real space [2]. Theoretical simulations that can provide an unambiguous interpretation and atomic description of obtained TERS images often rely on crude approximations of the local electric field [3]. In this work, we present a novel method to compute TERS images by combining Time Dependent Density Functional Theory (TDDFT) and Density Functional Perturbation Theory (DFPT) to calculate Raman cross sections with realistic local fields. The new approach allows for a fully ab initio atomistic description of the tip-molecule-surface system, and naturally incorporates chemical effects arising from the molecule-surface interaction. We show results for benzene and pyridine and discuss the importance of a realistic description of the local field, and self consistent evaluation of the electronic density response. Finally, we evaluate the use of 2D TERS imaging as an identification tool for defects in 2D materials. [1] M. Richard-Lacroix, et al., Chem. Rev. 56, 3922 (2017) [2] L. Joonhee, et al., Nature 568, 78 (2019) [3] P. Liu, X. Chen, H, Ye, and L. Jensen, ACS Nano 13, 9342 (2019)