Quasi-Diabatic Representation for Nonadiabatic Dynamics Propagation

Abstract

We develop a nonadiabatic dynamics propagation scheme that allows interfacing diabatic quantum dynamics methods with commonly used adiabatic electronic structure calculations. This scheme uses adiabatic states as the quasi-diabatic (QD) states during a short-time quantum dynamics propagation. At every dynamical propagation step, these QD states are updated based on a new set of adiabatic basis. Using the partial linearized density matrix (PLDM) path-integral method as one specific example for diabatic dynamics approaches, we demonstrate the accuracy of the QD scheme with a wide range of model nonadiabatic systems as well as the on-the-fly propagations with density functional tight-binding (DFTB) calculations. This study opens the possibility to combine accurate diabatic quantum dynamics methods with adiabatic electronic structure calculations for nonadiabatic dynamics propagations.

Investigating photoinduced proton coupled electron transfer reaction using quasi diabatic dynamics propagation

“…To address this discrepancy between the accurate diabatic quantum dynamics approaches and routinely available electronic structure calculations in the adiabatic states, we have developed Quasi-Diabatic (QD) propagation scheme, 48 a general approach which allows interfacing adiabatic electronic structure calculations with diabatic trajectory-based quantum dynamics methods. Here, we provide a brief summary of this scheme, whereas the details of the algorithm can be found in Ref.…”

“…Thus, the QD scheme provides a convenient propagation framework and a seamless interface for diabatic quantum dynamics approaches with adiabatic electronic structure calculations. 48…”

“…In this study, we apply a recently developed quasidiabatic (QD) 48 scheme to directly propagate PI-PCET quantum dynamics with diabatic Partial Linearized Density Matrix (PLDM) path-integral method. 49 As an example of recently developed accurate diabatic trajectorybased quantum dynamics approaches, PLDM uses a consistent dynamical footing for describing all DOFs.…”

Quasi-Diabatic Scheme for Nonadiabatic On-the-Fly Simulations

“…With the nuclear geometry closely following the reference geometry at every single propagation step, the QD basis forms a convenient and compact basis in each short-time propagation segment. To summarize, the QD scheme (40,41,48,49) uses the adiabatic states associated with a reference geometry as the quasi-diabatic states during a short-time quantum propagation, and dynamically update the definition of the QD states along the time-dependent nuclear trajectory. It allows a seamless interface between diabatic dynamics approaches with adiabatic electronic structure calculations.…”

“…To address this discrepancy, we have developed the Quasi-Diabatic (QD) propagation scheme (40,41) which provides a seamless interface between accurate diabatic quantum dynamics approaches and routinely available adiabatic electronic structure information for on-the-fly simulations. The key conceptual breakthrough behind the QD scheme is by recognizing that, in order to propagate quantum dynamics with diabatic dynamics approaches, one only needs locally well-defined diabatic states, as oppose to construct global dibabatic states from the diabatization procedures (2,(42)(43)(44)(45)(46)(47).…”