Excited electronic states and nonadiabatic processes play a key role in light (solar) to electrical or chemical energy conversion, ubiquitously encountered in nature and technology. In modelling these phenomena, the electronic and nuclear degrees of freedom need to be treated simultaneously. Still, due to the complexity and computational cost of treating them simultaneously, a more pragmatic and efficient way is to describe the system semiclassically. The system’s electronic part is modelled at a quantum level to obtain electronic energies and forces, which are then used to evolve the nuclei in an ab-initio molecular dynamics (AIMD) fashion. We are especially interested in modelling of nonadiabatic dynamics for the condensed phase.

A delta self-consistent field (ΔSCF) method is an efficient tool to study the excited electronic states by selectively optimizing a corresponding excited electron density associated with an electronic excited state of interest. The ΔSCF method has the issue of convergence for difficult cases or variation collapse to the ground electronic state. We are looking into ways to improve the ΔSCF convergence and also access higher excited states for more robust calculations of excited-state properties.

M. Mališ, S. Luber
ΔSCF with Subsystem Density Embedding for Efficient Nonadiabatic Molecular Dynamics in Condensed-Phase Systems
J. Chem. Theory Comput., 2021, 17, 3, 1653-1661

M. Mališ, S. Luber
Trajectory Surface Hopping Nonadiabatic Molecular Dynamics with Kohn– Sham ΔSCF for Condensed-Phase Systems
J. Chem. Theory Comput., 2020, 16, 7, 4071-4086

Group members working on this topic:

Momir Malis

Chandan Kumar

Eva Vandaele