Energy conserving variational dynamics with Gaussian wavepackets in the nonadiabatic regime
Year: 2026
Type: preprint
Abstract: We present a theoretical framework for a “trajectory”-driven nonadiabatic dynamics, that generalizes the variational Gaussian wavepacket approach to dynamics on multiple diabatic states. By applying the time-dependent variational principle to a single Gaussian wavepacket per state, we obtain a set of coupled equations for the Gaussian center and width parameters that include terms arising from the coupling potential. We investigate the role of these terms as they change the Gaussian time-evolution, and of the initial conditions on the wavefunction for several standard benchmarks of nonadiabatic dynamics, including a three-state and a two-dimensional model. The state populations obtained with the fully variational Gaussian dynamics is found in close agreement with exact quantum results. Finally, we demonstrate that the use of Gaussian wavefunction in nonadiabatic dynamics preserves the symplecticity of the variational space, which ensures the energy conservation and minimization of error when solving the time-dependent Schrödinger equation.
Source: ChemRxiv
Institution: University of South Carolina
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7223303762