Electronic quantum trajectories with quantum nuclei
Abstract
Quantum trajectory calculations for electrons are a useful tool in the field of molecular dynamics, e.g. to understand processes in ultrafast spectroscopy. They have, however, two limitation: On the one hand, such calculations are typically based on the BornOppenheimer approximation (BOA) and the electron dynamics for stationary nuclei is considered, thus neglecting quantum effects of the nuclei. On the other hand, even if the quantum nuclear motion would be taken into account, a BOA dynamics on a single potential energy surface would not provide any electron trajectories because the electronic part is treated as a stationary problem. By using the exact factorization method, we overcome these limitations and generalize the theory of electronic quantum trajectories to a fully quantummechanical treatment of the nuclei. After reviewing the timedependent theory of quantum hydrodynamics and quantum trajectories, we show that the nuclei can be viewed as a quantum clock for the electronic motion and we develop a fully quantummechanical clockdependent version of quantum hydrodynamics. This theory is used to obtain electronic trajectories for quantum nuclei, as is exemplified for a model system of a protoncoupled electron transfer dynamics. Our work generalizes the concept of quantum trajectories and lays the foundations for the development of trajectorybased simulation methods of electron dynamics beyond the BOA.
 Publication:

arXiv eprints
 Pub Date:
 September 2021
 arXiv:
 arXiv:2109.13632
 Bibcode:
 2021arXiv210913632S
 Keywords:

 Physics  Chemical Physics;
 Quantum Physics
 EPrint:
 arXiv admin note: substantial text overlap with arXiv:1911.13033