Long-lived electronic coherences from first principles

Electronic coherences can be leveraged to control molecular dynamics, but such control is limited by ultrafast decoherence driven by coupling between electronic excitations and molecular vibrations. With the goal of understanding and controlling electronic coherence in molecules, we introduce a first-principles approach that enables direct simulation of the creation and decay of electronic coherences in molecules. Simulations of long-lived experimentally observed coherences created upon multiphoton excitation of thiophene reveal coherent electronic motions within a dense manifold of Rydberg states, enabled by their relatively parallel potential energy surfaces.