Work

Optimal initial condition sampling for multi-configurational Ehrenfest dynamics

Year: 2026

Type: article

Abstract: The multi-configurational Ehrenfest (MCE) method offers a promising trajectory-based alternative to exact quantum dynamics for simulating non-adiabatic transitions, combining quantum and semiclassical elements through a basis of independent mean-field trajectories. A critical challenge in MCE lies in the optimal selection of initial trajectory conditions. In this work, we systematically evaluate different strategies for generating such initial conditions, including physical approaches based on Wigner and compressed Wigner distributions, as well as regular geometric constructions such as single- and multi-layered spherical and cubic grids. Among them, the cubic grid with a unit spacing in dimensionless coordinates emerges as a nearly universal and system-independent choice. We further demonstrate that, in systems with multiple conical intersections, trajectory cloning improves performance, but only after achieving convergence with respect to trajectory number using a well-constructed basis. Overall, MCE proves particularly advantageous for problems involving many coupled electronic states and offers flexibility for parallel implementation, making it especially relevant for the simulation of broadband excitation processes in attosecond science.

Source: The Journal of Chemical Physics

DOI: 10.1063/5.0303206

Authors: Thies Romig, Francesco Montorsi, Francesco Segatta, Marco Garavelli, Artur Nenov, Sergey I. Bokarev

Institutions: University of Rostock, University of Bologna, Technical University of Munich

Language: English

Topic: Spectroscopy and Quantum Chemical Studies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500

Funders: U.S. Department of Energy, Deutsche Forschungsgemeinschaft