Nonadiabatic Molecular Dynamics with Tight-Binding Fragment Molecular Orbitals

Akimov, Alexey V.

doi:10.1021/acs.jctc.6b00955

Cited by 40 publications

(66 citation statements)

References 152 publications

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“…Akimov has also developed a fragment molecular orbital approach in connection to TSH. 108 The method, based on a tight-binding extended Huckel theory and MSSH (see Section 3.2.3), has been applied to investigate systems with over 600 atoms for 5 ps.…”

Section: Niche Methodsmentioning

confidence: 99%

Recent Advances and Perspectives on Nonadiabatic Mixed Quantum–Classical Dynamics

2018

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Nonadiabatic mixed quantum-classical (NA-MQC) dynamics methods form a class of computational theoretical approaches in quantum chemistry tailored to investigate the time evolution of nonadiabatic phenomena in molecules and supramolecular assemblies. NA-MQC is characterized by a partition of the molecular system into two subsystems: one to be treated quantum mechanically (usually but not restricted to electrons) and another to be dealt with classically (nuclei). The two subsystems are connected through nonadiabatic couplings terms to enforce self-consistency. A local approximation underlies the classical subsystem, implying that direct dynamics can be simulated, without needing precomputed potential energy surfaces. The NA-MQC split allows reducing computational costs, enabling the treatment of realistic molecular systems in diverse fields. Starting from the three most well-established methods-mean-field Ehrenfest, trajectory surface hopping, and multiple spawning-this review focuses on the NA-MQC dynamics methods and programs developed in the last 10 years. It stresses the relations between approaches and their domains of application. The electronic structure methods most commonly used together with NA-MQC dynamics are reviewed as well. The accuracy and precision of NA-MQC simulations are critically discussed, and general guidelines to choose an adequate method for each application are delivered.

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Section: Niche Methodsmentioning

confidence: 99%

Recent Advances and Perspectives on Nonadiabatic Mixed Quantum–Classical Dynamics

2018

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“…We note in passing that our approach shares certain similarities with other semi-empirical implementations of non-adiabatic dynamics, e.g., the DFTB method of Elstner and co-workers 13,14 and the fragment molecular orbital method of Akimov. 33 Also in these approaches, the electronic Hamiltonian is directly constructed in a site or fragment basis requiring the calculation of site energies and electronic couplings. Yet, in our recent work, we went one step further by showing how the exact nuclear forces on the adiabatic electronic states can be obtained from the nuclear gradients in the diabatic representation.…”

Section: Introductionmentioning

confidence: 99%

Detailed balance, internal consistency, and energy conservation in fragment orbital-based surface hopping

Carof

Giannini

Blumberger

2017

The Journal of Chemical Physics

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We have recently introduced an efficient semi-empirical non-adiabatic molecular dynamics method for the simulation of charge transfer/transport in molecules and molecular materials, denoted fragment orbital-based surface hopping (FOB-SH) [J. Spencer et al., J. Chem. Phys. 145, 064102 (2016)]. In this method, the charge carrier wavefunction is expanded in a set of charge localized, diabatic electronic states and propagated in the time-dependent potential due to classical nuclear motion. Here we derive and implement an exact expression for the non-adiabatic coupling vectors between the adiabatic electronic states in terms of nuclear gradients of the diabatic electronic states. With the non-adiabatic coupling vectors (NACVs) available, we investigate how different flavours of fewest switches surface hopping affect detailed balance, internal consistency, and total energy conservation for electron hole transfer in a molecular dimer with two electronic states. We find that FOB-SH satisfies detailed balance across a wide range of diabatic electronic coupling strengths provided that the velocities are adjusted along the direction of the NACV to satisfy total energy conservation upon a surface hop. This criterion produces the right fraction of energy-forbidden (frustrated) hops, which is essential for correct population of excited states, especially when diabatic couplings are on the order of the thermal energy or larger, as in organic semiconductors and DNA. Furthermore, we find that FOB-SH is internally consistent, that is, the electronic surface population matches the average quantum amplitudes, but only in the limit of small diabatic couplings. For large diabatic couplings, inconsistencies are observed as the decrease in excited state population due to frustrated hops is not matched by a corresponding decrease in quantum amplitudes. The derivation provided here for the NACV should be generally applicable to any electronic structure approach where the electronic Hamiltonian is constructed in a diabatic electronic state basis.

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“…In this sense, it is also interesting to establish the diabatization procedure for such large systems. Some efforts were also made to build the diabatic models for large or extended systems, including the extended-Hückel approach 45 , energy-broadening analysis 34,38 , projection-operator approach and block diagonalization of Fock matrix 33,46 , constrained density functional theory (CDFT) 32,[47][48] , molecular orbital based fragmentation approaches [49][50] and so on. Particula r ly, these approaches were implemented to deal with the extended systems.…”

Section: Tocmentioning

confidence: 99%

“…projection-operator approach and block diagonalization of Fock matrix, constrained density functional theory (CDFT), molecular orbital based fragmenta tio n approaches As pointed out in the introduction part, it is certainly possible to construct the diabatic states by CDFT 32,[47][48] , the projection operation approach based on the block diagonalization of the Fock matrix 33,46 and fragment orbital approaches [49][50] .…”

Section: ( )mentioning

confidence: 99%

Diabatic Hamiltonian construction in van der Waals heterostructure complexes

et al. 2019

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A diabatization method is developed for the approximated description of the photoinduced charge separation/transfer processes in the van der Waals (vdW) heterostructure complex, which is based on the wavefunction projection approach using a plane wave basis set in the framework of the single-particle picture. We build the diabatic Hamiltonian for the description of the interlayer photoinduced hole-trans fer process of the two-dimensional vdW MoS2/WS2 heterostructure complexes. The diabatic Hamiltonian gives the energies of the localized valence band states (located at MoS2 and valence band states (located at WS2), as well as the couplings between them.The wavefunction projection method provides a practical and reasonable approach to construct the diabatic model in the description of photoinduced charge transfer processes in the vdW heterostructure complexes.

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Nonadiabatic Molecular Dynamics with Tight-Binding Fragment Molecular Orbitals

Cited by 40 publications

References 152 publications

Recent Advances and Perspectives on Nonadiabatic Mixed Quantum–Classical Dynamics

Recent Advances and Perspectives on Nonadiabatic Mixed Quantum–Classical Dynamics

Detailed balance, internal consistency, and energy conservation in fragment orbital-based surface hopping

Diabatic Hamiltonian construction in van der Waals heterostructure complexes

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