First-Principles Calculations of Excited-State Decay Rate Constants in Organic Fluorophores

The Journal of Physical Chemistry A, Journal Year: 2023, Volume and Issue: 127(48), P. 10033 - 10053

Published: Nov. 21, 2023

In this Perspective, we discuss recent advances made to evaluate from first-principles the excited-state decay rate constants of organic fluorophores, focusing on so-called static strategy. strategy, one essentially takes advantage Fermi's golden rule (FGR) at key points potential energy surfaces, a procedure that can be refined in variety ways. way, radiative constant straightforwardly obtained by integrating fluorescence line shape, itself determined vibronic calculations. Likewise, FGR allows for consistent calculation internal conversion (related non-adiabatic couplings) weak-coupling regime and intersystem crossing rates, therefore giving access estimates emission yields when no complex photophysical phenomenon is play. Beyond outlining underlying theories, summarize here results benchmarks performed various types highlighting both quality calculations accuracy relative energies are crucial reaching semiquantitative estimates. Finally, illustrate successes challenges determining quantum using series fluorophores.

Language: Английский

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Quantum Quality with Classical Cost: Ab Initio Nonadiabatic Dynamics Simulations Using the Mapping Approach to Surface Hopping

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(22), P. 5814 - 5823

Published: May 23, 2024

Nonadiabatic dynamics methods are an essential tool for investigating photochemical processes. In the context of employing first-principles electronic structure techniques, such simulations can be carried out in a practical manner using semiclassical trajectory-based or wave packet approaches. While all approaches applicable to necessarily approximate, it is commonly thought that offer inherent advantages over their counterparts terms accuracy and this trait simply comes at higher computational cost. Here we demonstrate mapping approach surface hopping (MASH), recently introduced nonadiabatic method, efficiently applied tandem with

Language: Английский

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Generalized Semiclassical Ehrenfest Method: A Route to Wave Function-Free Photochemistry and Nonadiabatic Dynamics with Only Potential Energies and Gradients

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(11), P. 4396 - 4426

Published: May 31, 2024

We reconsider recent methods by which direct dynamics calculations of electronically nonadiabatic processes can be carried out while requiring only adiabatic potential energies and their gradients. show that these understood in terms a new generalization the well-known semiclassical Ehrenfest method. This is convenient because it eliminates need to evaluate electronic wave functions matrix elements along mixed quantum-classical trajectories. The approximations procedures enabling this advance are curvature-driven approximation time-derivative coupling, generalized method, gradient correction scheme called (TDM) scheme. When spin–orbit coupling present, one carry fully basis using gradients calculated without plus elements. Even when neglected, method useful allows structure for vectors unavailable. In order place considerations context, article starts with review background material on trajectory surface hopping, scheme, incorporating decoherence. consider both internal conversion intersystem crossing. also several examples from our group successful applications approximation.

Language: Английский

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Machine learning photodynamics uncover blocked non-radiative mechanisms in aggregation-induced emission

Chem, Journal Year: 2024, Volume and Issue: 10(7), P. 2295 - 2310

Published: May 14, 2024

Language: Английский

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Beyond MD17: the reactive xxMD dataset

Scientific Data, Journal Year: 2024, Volume and Issue: 11(1)

Published: Feb. 20, 2024

Abstract System specific neural force fields (NFFs) have gained popularity in computational chemistry. One of the most popular datasets as a bencharmk to develop NFF models is MD17 dataset and its subsequent extension. These comprise geometries from equilibrium region ground electronic state potential energy surface, sampled direct adiabatic dynamics. However, many chemical reactions involve significant molecular geometrical deformations, for example, bond breaking. Therefore, inadequate represent reaction. To address this limitation MD17, we introduce new dataset, called Extended Excited-state Molecular Dynamics (xxMD) dataset. The xxMD involves nonadiabatic dynamics, energies are computed at both multireference wavefunction theory density functional theory. We show that diverse which reactions. Assessment on reveals significantly higher predictive errors than those reported variants. This work underscores challenges faced crafting generalizable model with extrapolation capability.

Language: Английский

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Machine learning photodynamics decode multiple singlet fission channels in pentacene crystal

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Jan. 30, 2025

Abstract Crystalline pentacene is a model solid-state light-harvesting material because its quantum efficiencies exceed 100% via ultrafast singlet fission. The fission mechanism in crystals disputed due to insufficient electronic information time-resolved experiments and intractable mechanical calculations for simulating realistic crystal dynamics. Here we combine multiscale multiconfigurational approach machine learning photodynamics understand competing mechanisms crystalline pentacene. Our simulations reveal coexisting charge-transfer-mediated coherent the channels herringbone parallel dimers. predicted time constants (61 33 fs) are excellent agreement with (78 35 fs). trajectories highlight essential role of intermolecular stretching between monomers generating multi-exciton state explain anisotropic phenomenon. machine-learning-photodynamics resolved elusive interplay structure vibrational relations, enabling fully atomistic excited-state dynamics quality

Language: Английский

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Legion: A Platform for Gaussian Wavepacket Nonadiabatic Dynamics

Journal of Chemical Theory and Computation, Journal Year: 2025, Volume and Issue: unknown

Published: March 2, 2025

Nonadiabatic molecular dynamics is crucial in investigating the time evolution of excited states systems. Among various methods for performing such dynamics, those employing frozen Gaussian wavepacket propagation, particularly multiple spawning approach, offer a favorable balance between computational cost and reliability. It propagates on-the-fly trajectories used to build propagate nuclear wavepacket. Despite its potential, efficient, flexible, easily accessible software propagation less common compared other methods, as surface hopping. To address this, we present Legion, that facilitates development application classical-trajectory-guided quantum methods. The version presented here already contains highly flexible fully functional ab initio implementation, with different strategies improve efficiency. Legion written Python data management NumPy/Fortran numerical operations. created under umbrella Newton-X platform inherits all electronic structure interfaces beyond direct interfaces. also new approximations allow it circumvent computation nonadiabatic coupling, extending can be dynamics. We test, validate, demonstrate Legion's functionalities through fulvene (CASSCF CASPT2) DMABN (TDDFT).

Language: Английский

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Conical Intersections Studied by the Configuration-Interaction-Corrected Tamm–Dancoff Method

Journal of Chemical Theory and Computation, Journal Year: 2025, Volume and Issue: unknown

Published: March 18, 2025

Conical intersections directly mediate the internal energy conversion in photoinduced processes a wide range of chemical and biological systems. Because Brillouin theorem, many conventional electronic structure methods, including configuration interaction with single excitations from Hartree-Fock reference time-dependent density functional theory either linear response approximation (TDDFT) or Tamm-Dancoff (DFT-TDA), have wrong dimensionality for conical between ground state (S0) first excited (S1) same multiplicity. This leads to unphysical crossings. Here, we implement assess configuration-interaction-corrected (CIC-TDA) that restores correct by coupling intersecting state. We apply CIC-TDA method S1/S0 ammonia (NH3), ethylene (C2H4), bithiophene (C8H6S2), azobenzene (C12H10N2), 11-cis retinal protonated Schiff base (PSB11) vacuo. show this black-box approach can produce potential surfaces (PESs) comparable accuracy multireference wave function methods. The validated here allow cost-efficient explorations electronically nonadiabatic dynamics, especially large molecules complex

Language: Английский

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A comparative study on adiabatic and nonadiabatic dynamics of the H(2S) + NaH(X1Σ+) reaction

Chemical Physics, Journal Year: 2024, Volume and Issue: 583, P. 112324 - 112324

Published: May 5, 2024

Language: Английский

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Semiclassical Nonadiabatic Molecular Dynamics Using Linearized Pair-Density Functional Theory

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(20), P. 8741 - 8748

Published: Oct. 9, 2024

Nonadiabatic molecular dynamics is an effective method for modeling nonradiative decay in electronically excited molecules. Its accuracy depends strongly on the quality of potential energy surfaces, and its affordability long direct-dynamic simulations with adequate ensemble averaging cost required electronic structure calculations. Linearized pair-density functional theory (L-PDFT) a recently developed post-self-consistent-field multireference that can model surfaces similar to expensive perturbation theories but at computational underlying multiconfiguration self-consistent field method. Here, we integrate SHARC PySCF code utilize L-PDFT nonadiabatic calculations use combined programs study photoisomerization reaction

Language: Английский

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