Mainz 2026 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 9: Chirality II
MO 9.3: Vortrag
Dienstag, 3. März 2026, 11:45–12:00, P 110
Robust Prediction of Plasmonic Enhanced Circular Dichroism — •Maria J. Weseloh1, Mikael Kuisma2, Tuomas Rossi3, Xi Chen4, and Patrick Rinke1,5 — 1Aalto University, Finland — 2Technical University of Denmark, Denmark — 3CSC - IT Center for Science, Finland — 4Lanzhou University, China — 5Technical University of Munich, Germany
Chirality can determine properties such as toxicity, making detection critical for health and environmental safety. Circular dichroism (CD) spectroscopy is a key technique for chiral discrimination but is often limited by weak chiral signals below measurable thresholds. Plasmonic enhancement of molecular circular dichroism by nanoparticles (peCD) enables detection of molecular chirality where conventional CD fails. Real-time time-dependent density functional theory (RT-TDDFT) in principle enables predictive peCD spectra, but in practice a fundamental issue arises: in the traditional length gauge, CD spectra depend on the arbitrary choice of coordinate-system origin - as highlighted in Phys. Rev. B 110, 115423 (2024). We overcome this limitation by implementing a velocity-gauge formulation of RT-TDDFT. Unlike the length gauge approach, where the dipole operator introduces explicit spatial dependence, the velocity gauge employs the momentum operator and removes this spatial dependence. Calculations across 27 distinct origins for molecules and nanoparticle-molecule systems demonstrate a robust origin insensitivity, even with moderately sized basis sets. Thanks to its computational efficiency, our method supports predictive and practical simulations of realistically large systems.
Keywords: Circular Dichroism; TDDFT; Plasmonnic Nanoparticles; Light-Matter Interactions; first principles