Exciton Dissociation in a Model Organic Interface: Excitonic State-Based Surface Hopping versus Multiconfigurational Time-Dependent Hartree

The Journal of Physical Chemistry Letters, Journal Year: 2022, Volume and Issue: 13(31), P. 7105 - 7112

Published: July 28, 2022

Quantum dynamical simulations are essential for a molecular-level understanding of light-induced processes in optoelectronic materials, but they tend to be computationally demanding. We introduce an efficient mixed quantum-classical nonadiabatic molecular dynamics method termed eXcitonic state-based Surface Hopping (X-SH), which propagates the electronic Schrödinger equation space local excitonic and charge-transfer states, coupled thermal motion nuclear degrees freedom. The is applied exciton decay 1D model fullerene–oligothiophene junction, results compared ones from fully quantum treatment at level Multilayer Multiconfigurational Time-Dependent Hartree (ML-MCTDH) approach. Both methods predict that charge-separated states formed on 10–100 fs time scale via multiple "hot-exciton dissociation" pathways. demonstrate X-SH promising tool advancing simulation photoexcited true nanomaterials scale.

Language: Английский

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Evaluating the anharmonicity contributions to the molecular excited state internal conversion rates with finite temperature TD-DMRG

The Journal of Chemical Physics, Journal Year: 2021, Volume and Issue: 154(21)

Published: June 3, 2021

In this work, we propose a new method to calculate molecular nonradiative electronic relaxation rates based on the numerically exact time-dependent density matrix renormalization group theory. This could go beyond existing frameworks under harmonic approximation (HA) of potential energy surface (PES) so that anharmonic effect be considered, which is vital importance when gap much larger than vibrational frequency. We internal conversion (IC) in two-mode model with Morse investigate validity HA. find HA unsatisfactory unless only lowest several states lower state are involved transition process adiabatic excitation relatively low. As increases, first underestimates and then overestimates IC excited PES shifts toward dissociative side ground PES. On contrary, slightly repulsive side. both cases, higher temperature enlarges error real example demonstrate effectiveness scalability method, azulene from S1 S0 ab initio approximated by one-mode representation. The calculated consistent analytically results. 30%–40%

Language: Английский

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All-Atom Nonadiabatic Dynamics Simulation of Hybrid Graphene Nanoribbons Based on Wannier Analysis and Machine Learning

ACS Applied Materials & Interfaces, Journal Year: 2022, Volume and Issue: 14(20), P. 22929 - 22940

Published: Jan. 31, 2022

Trajectory surface hopping combined with ab initio electronic structure calculations is a popular and powerful approach for on-the-fly nonadiabatic dynamics simulations. For large systems, however, this remains significant challenge because of the unaffordable computational cost large-scale calculations. Here, we present an efficient divide-and-conquer to construct system Hamiltonian based on Wannier analysis machine learning. In detail, under investigation first decomposed into small building blocks, then all possible segments formed by blocks within cutoff distance are found out. Ab molecular carried out generate sequence geometries each equivalent segment periodicity. The matrices in maximum localized function (MLWF) basis obtained utilized train artificial neural networks (ANNs) structure-dependent elements. Taking advantage orthogonality spatial locality MLWFs, one-electron at arbitrary geometry can be directly constructed trained ANNs. As demonstrations, study charge transport zigzag graphene nanoribbon (GNR), coved GNR, series hybrid GNRs state-of-the-art method. interplay between delocalized states determine electron GNRs. Our has successfully studied >10 000 atoms, paving way reliable all-atom simulation general systems.

Language: Английский

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Nonadiabatic Coupling in Trajectory Surface Hopping: Accurate Time Derivative Couplings by the Curvature-Driven Approximation

Journal of Chemical Theory and Computation, Journal Year: 2023, Volume and Issue: 19(19), P. 6577 - 6588

Published: Sept. 29, 2023

Trajectory surface hopping (TSH) is a widely used mixed quantum-classical dynamics method that to simulate molecular with multiple electronic states. In TSH, time-derivative coupling employed propagate the coefficients and in way determine when state on which nuclear trajectory propagated switches. this work, we discuss nonadiabatic TSH algorithms employing curvature-driven approximation overlap-based time derivative couplings, report test calculations six photochemical reactions where compare results one another analytic vectors. We correct previous published thanks bug found software. also provide additional, more detailed studies of couplings. Our show good agreement between algorithms.

Language: Английский

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Nonadiabatic Dynamics Simulations for Photoinduced Processes in Molecules and Semiconductors: Methodologies and Applications

Journal of Chemical Theory and Computation, Journal Year: 2023, Volume and Issue: 19(23), P. 8491 - 8522

Published: Nov. 20, 2023

Nonadiabatic dynamics (NAMD) simulations have become powerful tools for elucidating complicated photoinduced processes in various systems from molecules to semiconductor materials. In this review, we present an overview of our recent research on photophysics molecular and periodic materials with the aid ab initio NAMD simulation methods implemented generalized trajectory surface-hopping (GTSH) package. Both theoretical backgrounds applications developed are presented detail. For systems, linear-response time-dependent density functional theory (LR-TDDFT) method is primarily used model electronic structures owing its balanced efficiency accuracy. Moreover, efficient algorithms calculating nonadiabatic coupling terms (NACTs) spin–orbit couplings (SOCs) been coded into package increase efficiency. combination analysis techniques, can explore mechanistic details a range including charge separation energy transfer organic donor–acceptor structures, ultrafast intersystem crossing (ISC) transition metal complexes (TMCs), exciton aggregates. materials, simulating carrier within framework Kohn–Sham (KS-DFT), which SOC effects explicitly accounted using two-component, noncollinear DFT method. Using method, investigated at interface variety van der Waals (vdW) heterojunctions, such as two-dimensional dichalcogenides (TMDs), carbon nanotubes (CNTs), perovskites-related systems. Recently, extended LR-TDDFT-based allowing us study excitonic process. These results demonstrate that exploring photodynamics future studies, be employed elucidate experimental phenomena reveal microscopic well rationally design novel photofunctional desired properties.

Language: Английский

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