A multiconfiguration pair-density functional theory-based approach to molecular junctions

Due to their small size and unique properties, single-molecule electronics have long seen research interest from experimentalists theoreticians alike. From a theoretical standpoint, modeling these systems using electronic structure theory can be difficult due the importance of electron correlation in determination molecular this computationally expensive consider, particularly multiconfigurational energy. In work, we develop new approach for study systems, denoted NEGF-MCPDFT, which combines multiconfiguration pair-density functional (MCPDFT) with non-equilibrium Green’s function formalism (NEGF). The use MCPDFT NEGF allows efficient inclusion both static dynamic correlations description junction’s structure. Complete active space self-consistent field wave functions are used as references calculation, any method, effort must made determine proper orbital character include space. We perform conductance transmission calculations on series alkanes (predominantly single-configurational character) benzyne (multiconfigurational character), exploring role that selection has computed results. For alkane junctions explored (where dominates), MCPDFT-NEGF results agree well DFT-NEGF junction (which significant correlation), see clear differences evidence NEGF-MCPDFT is capturing additional effects beyond those provided by Perdew–Burke–Ernzerhof functional.