Insights to Orientation Dependence of Molecular Conduction Modeled by High-Level Quantum Embedding

This work investigates how molecular orientation and electrode-molecule interactions influence conductance variations in single-molecule junctions using recently introduced methods that utilize quantum embedding within the NEGF framework. By generating conductance histograms from transmission functions for two experimentally studied systems, we assess the ability of several embedding schemes and conventional DFT approaches to reproduce experimentally observed distributions. The results show that while the wavefunction-in-DFT, SOS-ADC(2)-in-PBE method provides the most balanced description of both mean conductance and histogram width, no method fully captures the behavior of the more rigid dithienophosphole system, likely due to limitations of the underlying structural sampling. These findings highlight the importance of realistic configurational sampling and demonstrate that conductance histograms offer a sensitive benchmark for evaluating theoretical transport methodologies.