Dresden 2026 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

O: Fachverband Oberflächenphysik

O 14: Ultrafast electron dynamics at surface and interfaces I

O 14.7: Talk

Monday, March 9, 2026, 16:45–17:00, TRE/MATH

Realistic nuclear ensembles for electronic excitation dynamics — •Hannah Bertschi, George Trenins, and Mariana Rossi — MPI for the Structure and Dynamics of Matter, Hamburg, Germany

Understanding how large-amplitude anharmonic nuclear motion influences electronic excitations is essential for explaining related phenomena in weakly-bound systems. To model charge transfer and vibronic spectra, we employ real-time time-dependent density functional theory coupled to multitrajectory Ehrenfest dynamics. In this approach, nuclear anharmonicity is incorporated through the sampling of initial conditions. In contrast to more conventional methods, we generate nuclear configurations and momenta using quantum thermostat molecular dynamics [1]. The resulting distributions of nuclear positions and momenta agree well with exact quantum references obtained from path-integral molecular dynamics, even for systems with large-amplitude motion such as the water dimer. However, the quantum thermostat does not perfectly capture the anharmonic zero-point energy of every degree of freedom, which can be mitigated by carefully choosing the parametrization of the thermostat. We show that the initial nuclear conditions of a water dimer on phenanthrene have a strong impact on both the direction and magnitude of charge transfer. Moreover, the nonadiabatic dynamics can even reverse the direction of the transfer. [1] M. Ceriotti et al., Phys. Rev. Lett. 103, 030603 (2009).

Keywords: Ehrenfest dynamics; time-dependent density functional theory; quantum thermostat; vibronic absorption spectra; charge transfer