Surface Hopping Dynamics on Vibronic Coupling Models

Zobel, J. Patrick; Heindl, Moritz; Plasser, Felix; Mai, Sebastian; González, Leticia

doi:10.1021/acs.accounts.1c00485

Cited by 46 publications

(64 citation statements)

References 68 publications

(131 reference statements)

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“…[26] The ML approaches have also been used to assist the full quantum wave packet dynamics. [32][33][34] With the high fidelity and low cost of ML techniques, the ML-NAMD technique now shares the spotlight with the other efficient methods parameterized from multiconfigurational time-dependent Hartree (MCTDH), for example, linear vibronic coupling (LVC) model [35] for the state-of-the-art explorations, discoveries, and predictions of photochemical reactions.…”

Section: Chemistry-a European Journalmentioning

confidence: 99%

Excited‐State Distortions Promote the Photochemical 4π‐Electrocyclizations of Fluorobenzenes via Machine Learning Accelerated Photodynamics Simulations

Lopez

2022

Chemistry A European J

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Benzene fluorination increases chemoselectivities for Dewar-benzenes via 4π-disrotatory electrocyclization. However, the origin of the chemo-and regioselectivities of fluorobenzenes remains unexplained because of the experimental limitations in resolving the excited-state structures on ultrafast timescales. The computational cost of multiconfigurational nonadiabatic molecular dynamics simulations is also currently cost-prohibitive. We now provide high-fidelity structural information and reaction outcome predictions with machine-learning-accelerated photodynamics simulations of a series of fluorobenzenes, C 6 F 6-n H n , n = 0-3, to study their S 1 !S 0 decay in 4 ns. We trained neural networks with XMS-CASPT2(6,7)/aug-cc-pVDZ calculations, which reproduced the S 1 absorption features with mean absolute errors of 0.04 eV (< 2 nm). The predicted nonradiative decay constants for C 6 F 4 H 2 , C 6 F 6 , C 6 F 3 H 3 , and C 6 F 5 H are 116, 60, 28, and 12 ps, respectively, in broad qualitative agreement with the experiments. Our calculations show that a pseudo Jahn-Teller distortion of fluorinated benzenes leads to an S 1 localminimum region that extends the excited-state lifetimes of fluorobenzenes. The pseudo Jahn-Teller distortions reduce when fluorination decreases. Our analysis of the S 1 dynamics shows that the pseudo-Jahn-Teller distortions promote an excited-state cis-trans isomerization of a π C-C bond. We characterized the surface hopping points from our NAMD simulations and identified instantaneous nuclear momentum as a factor that promotes the electrocyclizations.

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Section: Chemistry-a European Journalmentioning

confidence: 99%

Excited‐State Distortions Promote the Photochemical 4π‐Electrocyclizations of Fluorobenzenes via Machine Learning Accelerated Photodynamics Simulations

Lopez

2022

Chemistry A European J

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“…Alternative methods leveraged the use of density functional tight-binding (DFTB), − semiempirical, − or hybrid quantum mechanical/molecular mechanics , approaches. Several fragment-based schemes ,,− and vibronic coupling methods were developed to improve the scalability of the methods. Alternatively, NAC-free approaches ,− have been explored as a route to inexpensive NA-MD simulations.…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic Molecular Dynamics with Extended Density Functional Tight-Binding: Application to Nanocrystals and Periodic Solids

Shakiba

Stippell

et al. 2022

J. Chem. Theory Comput.

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In this work, we report a new methodology for nonadiabatic molecular dynamics calculations within the extended tight-binding (xTB) framework. We demonstrate the applicability of the developed approach to finite and periodic systems with thousands of atoms by modeling “hot” electron relaxation dynamics in silicon nanocrystals and electron–hole recombination in both a graphitic carbon nitride monolayer and a titanium-based metal–organic framework (MOF). This work reports the nonadiabatic dynamic simulations in the largest Si nanocrystals studied so far by the xTB framework, with diameters up to 3.5 nm. For silicon nanocrystals, we find a non-monotonic dependence of “hot” electron relaxation rates on the nanocrystal size, in agreement with available experimental reports. We rationalize this relationship by a combination of decreasing nonadiabatic couplings related to system size and the increase of available coherent transfer pathways in systems with higher densities of states. We emphasize the importance of proper treatment of coherences for obtaining such non-monotonic dependences. We characterize the electron–hole recombination dynamics in the graphitic carbon nitride monolayer and the Ti-containing MOF. We demonstrate the importance of spin-adaptation and proper sampling of surface hopping trajectories in modeling such processes. We also assess several trajectory surface hopping schemes and highlight their distinct qualitative behavior in modeling the excited-state dynamics in superexchange-like models depending on how they handle coherences between nearly parallel states.

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“…Our dynamics methodology is based on full dimensional trajectory surface hopping (TSH) in conjunction with a linear vibronic coupling (LVC) model. 28,29 We follow a hybrid approach, 30 recently developed by one of us, based on the combination of time-dependent density functional theory (TD-DFT) PESs and multiconfigutational second order perturbation theory (CASPT2) SOCs. Further methodological details are described below, in Supplementary Note 1, and ref.…”

Section: Methodsmentioning

confidence: 99%

Branching mechanism of photoswitching in Fe(II) polypyridyl complexes explained by full singlet-triplet-quintet dynamics

Rozgonyi

Vankó

Pápai

2022

Preprint

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It has long been known that irradiation with visible light converts Fe(II) polypyridines from their low-spin (singlet) to high-spin (quintet) state, yet mechanistic interpreation of the photorelaxation remains contraversal. Herein, we simulate the full singlet-triplet-quintet dynamics of the [Fe(terpy)2]2+ (terpy = 2,2’:6’,2’’-terpyridine) complex in full dimension, in order to clarify the complex photodynamics. Importantly, we report a branching mechanism with two sequential components: 3MLCT → 3MC(3T2g) → 5MC and 3MLCT → 3MC(3T2g) → 3MC(3T1g) → 5MC (MLCT = metal-to-ligand charge transfer, MC = metal-centered). While the direct 3MLCT → 5MC mechanism is considered as a relevant alternative, we show that it could only be operative and thus lead to competing pathways in the absence of 3MC states. The quintet state is populated on the sub-picosecond timescale involving non-exponential dynamics and coherent Fe-N breathing oscillations. The results are in agreement with the available time-resolved experimental data on Fe(II) polypiridines, and fully describe the photorelaxation dynamics.

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Surface Hopping Dynamics on Vibronic Coupling Models

Cited by 46 publications

References 68 publications

Excited‐State Distortions Promote the Photochemical 4π‐Electrocyclizations of Fluorobenzenes via Machine Learning Accelerated Photodynamics Simulations

Excited‐State Distortions Promote the Photochemical 4π‐Electrocyclizations of Fluorobenzenes via Machine Learning Accelerated Photodynamics Simulations

Nonadiabatic Molecular Dynamics with Extended Density Functional Tight-Binding: Application to Nanocrystals and Periodic Solids

Branching mechanism of photoswitching in Fe(II) polypyridyl complexes explained by full singlet-triplet-quintet dynamics

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