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Description
We present a density-functional theory (DFT) and time-dependent density-functional theory (TDDFT) investigation of the adsorption behaviour of heptahelicene (7HC) on Ag(110). This molecule serves as a model system for studying helical currents induced in chiral, spiral-like molecules on surfaces and has been discussed as an efficient spin filter due to the chirality-induced spin selectivity (CISS) effect. In our study, we first explore the adsorption energy landscape by sampling multiple initial configurations and performing local relaxations by using a repeated-slab approach with a van-der-Waals corrected GGA functional. The most favourable geometries are then examined in terms of work-function changes, charge-density-difference distributions, and projected densities of states. We further simulate photoemission momentum maps of the frontier molecular orbitals within photoemission orbital tomography and compare them with experimental angle-resolved photoemission data. This combined analysis provides a comprehensive understanding of the molecule–substrate interaction. It also forms the basis for future experimental studies of THz electric-field induced helical currents in the 7HC molecule. We simulate such transient currents by real-time, real-space TDDFT simulations for a gas phase heptahelicene molecule providing valuable insights into the induced charge rearrangements and currents.