Trajectory‐Based Nonadiabatic Dynamics with Time‐Dependent Density Functional Theory

Abstract

Understanding the fate of an electronically excited molecule constitutes an important task for theoretical chemistry, and practical implications range from the interpretation of atto- and femtosecond spectroscopy to the development of light-driven molecular machines, the control of photochemical reactions, and the possibility of capturing sunlight energy. However, many challenging conceptual and technical problems are involved in the description of these phenomena such as 1) the failure of the well-known Born-Oppenheimer approximation; 2) the need for accurate electronic properties such as potential energy surfaces, excited nuclear forces, or nonadiabatic coupling terms; and 3) the necessity of describing the dynamics of the photoexcited nuclear wavepacket. This review provides an overview of the current methods to address points 1) and 3) and shows how time-dependent density functional theory (TDDFT) and its linear-response extension can be used for point 2). First, the derivation of Ehrenfest dynamics and nonadiabatic Bohmian dynamics is discussed and linked to Tully's trajectory surface hopping. Second, the coupling of these trajectory-based nonadiabatic schemes with TDDFT is described in detail with special emphasis on the derivation of the required electronic structure properties.

GPU-Accelerated State-Averaged Complete Active Space Self-Consistent Field Interfaced with Ab Initio Multiple Spawning Unravels the Photodynamics of Provitamin D3

“…[37][38] Thus, TSH coupled to LR-TDDFT has been used for a variety of applications. [39][40][41][42] More recently, AIMS was interfaced with GPU-accelerated LR-TDDFT and applied to study the photophysics of 4-(dimethylamino)benzonitrile (DMABN) (unpublished results). Despite its successes, LR-TDDFT has some well-known shortcomings that are due to practical approximations required to make the method tractable.…”

Communication: Exciton analysis in time-dependent density functional theory: How functionals shape excited-state characters

“…(1) is used in the current implementation, but we note for completeness that this is not a rigorous assignment as wavefunctions do not exist in TDDFT, and a different formalism suggests the use of additional scaling factors. 2,32,33 In the case of the Tamm-Dancoff approximation (TDA), 34 the same formalism is applied with the exception that the Y I ia terms vanish. Properties of the exciton wavefunction can be directly calculated as operator expectation values…”

Ab initio and semi-empirical Molecular Dynamics simulations of chemical reactions in isolated molecules and in clusters

“…72 A key issue is the evaluation of the derivative couplings that drive the non-adiabatic transitions between different electronic states. 73 This was accomplished analytically, 73 [77][78][79] Also these authors find that the TD-DFT potential surfaces seem to have adequate accuracy for realistic non-adiabatic systems. 77 We turn attention now to on-the-fly trajectory simulations that use ab initio multi-reference electronic structure methods to describe the potential surfaces for the processes considered here.…”