Designing Active Spaces with Periodic-like Properties for Charge Transport in Multiconfigurational Nanoscale Systems*

Fundamentally quantum charge transport systems such as molecular electronics require a fully quantum transport approach that consistently captures both dynamic and multireference electron correlation effects. We previously introduced a unique methodology for integrating multiconfigurational electronic structure methods, particularly multiconfiguration pair density functional theory (MC-PDFT), within a non-equilibrium Green's function (NEGF) formalism. This approach uses an active space to capture both electronic correlation types for a set of transport-relevant orbitals while treating the non-active orbitals with density functional theory. This approach creates a new theoretical challenge as limited to no design principles exist for selecting active spaces for nanoscale charge transport problems. In this talk, I will demonstrate design principles for creating active spaces for charge transport that maintain periodic-like characteristics and that can capture quantum transport phenomena in nanoscale electronics such as conductance decay reversals.