Jankunas Dissertation Award (Finalists): A phase-space electronic structure framework to nonadiabatic dynamics and spin chemistry

The Born-Oppenheimer (BO) approximation is the cornerstone of molecular dynamics and spectroscopy, defining electronic structure at fixed nuclear geometries and enabling nearly all modern quantum chemistry calculation. While its breakdown near curve crossings and conical intersections is well understood in photochemistry and electron transfer, BO also exhibits a more subtle dynamical failure: classical BO dynamics does not correctly account for the electronic linear and angular momentum induced by nuclear motion and consequently fails to conserve total momentum even in ground-state dynamics.

In this talk, we will present a phase-space electronic structure framework that systematically restores momentum conservation and recovers physically meaningful electronic currents during nuclear motion. By incorporating both nuclear coordinates and nuclear momenta into electronic Hamiltonians, this approach yields improved vibrational energetics, enhances optical responses such as vibrational circular dichroism, and provides new interpretive power for understanding angular-momentum transfer between electrons, spin and nuclei.

Finally, we will discuss how this phase-space framework opens a new conceptual pathway toward nuclear momentum-driven phenomena such as spin-Coriolis coupling, which may offer microscopic insight into chiral induced spin selectivity and other magnetic field dependent effects.