Ultrafast electron diffraction of photoexcited gas-phase cyclobutanone predicted by ab initio multiple cloning simulations

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(16)

Published: April 25, 2024

We present the result of our calculations ultrafast electron diffraction (UED) for cyclobutanone excited into S2 electronic state, which is based on non-adiabatic dynamics simulations with Ab Initio Multiple Cloning (AIMC) method structure calculated at SA(3)-CASSCF(12,12)/aug-cc-pVDZ level theory. The key features in UED pattern were identified, can be used to distinguish between reaction pathways observed AIMC dynamics, although there a significant overlap representative signals due structural similarity products. compared experiment.

Language: Английский

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SPADE 1.0: A Simulation Package for Non-Adiabatic Dynamics in Extended Systems

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

Published: March 24, 2025

Nonadiabatic molecular dynamics (NAMD) simulations are crucial for revealing the underlying mechanisms of photochemical and photophysical processes. Typical NAMD simulation software packages rely on on-the-fly ab initio electronic structure nonadiabatic coupling calculations, thus become challenging when dealing with large complex systems. We here introduce a new Simulation Package non-Adiabatic Dynamics in Extended systems (SPADE), which is designed to address limitations traditional surface hopping methods these problems. By design, SPADE enables users define arbitrary quasi-diabatic Hamiltonians through parametrized functions incorporates variety algorithms (e.g., global flux probabilities, crossing decoherence corrections), can realize efficient reliable without using couplings at all. All employed expressions diabatic Hamiltonian matrix elements be flexibly set input files. mainly written Fortran based modular design has great capacity further implementation methods. used simulate both model atomistic as long proper provided. As demonstrations, series representative models studied show main features capabilities.

Language: Английский

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Machine Learning Framework for Modeling Exciton Polaritons in Molecular Materials

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(2), P. 891 - 901

Published: Jan. 3, 2024

A light–matter hybrid quasiparticle, called a polariton, is formed when molecules are strongly coupled to an optical cavity. Recent experiments have shown that polariton chemistry can manipulate chemical reactions. Polariton collective phenomenon, and its effects increase with the number of in However, simulating ensemble excited state cavity mode theoretically computationally challenging. advances machine learning (ML) techniques promising capabilities modeling ground-state systems. This work presents general protocol predict excited-state properties, such as energies, transition dipoles, nonadiabatic coupling vectors hierarchically interacting particle neural network. ML predictions then applied compute potential energy surfaces electronic spectra prototype azomethane molecule scenario. These computational tools provide much-needed framework model understand many molecules' emerging chemistry.

Language: Английский

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The development of the QM/MM interface and its application for the on-the-fly QM/MM nonadiabatic dynamics in JADE package: Theory, implementation, and applications

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(23)

Published: June 17, 2024

Understanding the nonadiabatic dynamics of complex systems is a challenging task in computational photochemistry. Herein, we present an efficient and user-friendly quantum mechanics/molecular mechanics (QM/MM) interface to run on-the-fly dynamics. Currently, this consists independent set codes designed for general-purpose use. demonstrate ability feasibility QM/MM by integrating it with our long-term developed JADE package. Tailored handle processes various systems, especially condensed phases protein environments, delve into theories, implementations, applications The approach established within framework additive scheme, employing electrostatic embedding, link-atom inclusion, charge-redistribution schemes treat boundary. Trajectory surface-hopping are facilitated using fewest switches algorithm, encompassing classical treatments nuclear electronic motions, respectively. Finally, report simulations two typical systems: azomethane water retinal chromophore PSB3 environment. Our results not only illustrate power program but also reveal important roles environmental factors processes.

Language: Английский

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Ab initio spin-mapping non-adiabatic dynamics simulations of photochemistry

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(8)

Published: Feb. 25, 2025

We perform on-the-fly non-adiabatic molecular dynamics simulations using the recently developed spin-mapping formalism. Two quantum approaches based on this mapping formalism, (i) fully linearized Spin-LSC and (ii) partially Spin-PLDM, are explored quasi-diabatic propagation scheme. have performed in four ab initio models for which benchmark multiple spawning (AIMS) data been published. find that spin-LSC previously reported symmetric quasi-classical (SQC) provide nearly equivalent population dynamics. While we expected more involved spin-PLDM method to superior accuracy compared other mapping-based approaches, SQC spin-LSC, found it with AIMS results. further explore underpinnings of correlation function by decomposing its N2 density matrix-focused initial conditions, where N is number states subsystem. Finally, an approximate form function, simplifies simulation reduces computational costs from N.

Language: Английский

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Pinning Excited State Self-Trapping with All-Benzene Trefoil Knot

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 4228 - 4235

Published: April 21, 2025

The synthesis of novel carbon nanostructures with unique topologies expands the landscape organic molecules, introducing new chemical properties and potential applications. Carbon nanorings, composed cyclic paraphenylene (CPP) chains, serve as a versatile scaffold for designing materials molecular architectures that impact their optical photoinduced dynamics. These alter balance between competing π-conjugation effects, high bending strain energies, steric hindrances imposed by rearrangement structures. Here, we explore dynamics all-benzene trefoil knot using nonadiabatic excited-state We show how its absorption spectra can be modeled particle in box constrained to geometry, analyze internal conversion process following photoexcitation. Our findings reveal an exciton intraring migration governed winding chain, ultimately leading self-trapping at specific curvature regions knot. This behavior contrasts nondeterministic corresponding CPP, where localization occurs randomly across different phenylene units. results highlight ability knots control through curvature, tension, planarization positioning these promising candidates future technological precisely manipulate electronic characteristics is essential developing more efficient devices.

Language: Английский

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Energy Transfer Mechanisms in Large Low-Bandgap Polymers from Time-Resolved Experiments and Nonadiabatic Molecular Dynamics Calculations

Chemistry of Materials, Journal Year: 2025, Volume and Issue: 37(10), P. 3769 - 3775

Published: May 14, 2025

Conjugated polymers offer unprecedented chemical tunability for modulating energy transfer in a multitude of infrared light applications. In this work, we use combination time-resolved spectroscopic experiments and nonadiabatic molecular dynamics calculations to probe the photochemistry nonradiative transitions recently synthesized narrow bandgap donor-acceptor conjugated polymer based on alternating cyclopentadithiophene electronegative benzothiadiazole heterocycles. Using large-scale semi-empirical dynamics, which can treat large 260-atom hexamer, calculate an S5 → S1 lifetime 34.75 fs, is consistent with our data. Our simulations suggest that vibronic motions central carbons functional groups are predominantly involved transitions, excitation becomes more localized monomer fragment over time. The combined work provides mechanistic insight into functionalities be tuned enhance other prospective low-bandgap materials.

Language: Английский

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Rules of triplet state electron impact neutral dissociation in plasma from molecular dynamics simulations and an electrophore model

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films, Journal Year: 2025, Volume and Issue: 43(4)

Published: May 29, 2025

Electron impact driven neutral dissociation of molecules that is important in low temperature plasma investigated. Despite its importance for technologies microelectronics manufacturing, this process has received almost no attention from the computational chemistry community, which decades been focused on photodissociation. Simulations are performed several fluorinate-organic their lowest triplet state, populated via electron excitation. Their plasmas recently studied experimentally and pathways have shown to differ those singlet ground state. Rules determine proposed rationalized analysis an ensemble trajectories, highlighting common pathways. These rules can help find new use future technologies, produce a desired chemical composition plasma, enhancing selectivity, etch rates, environmental benefits.

Language: Английский

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Dissociation of Hydrofluorocarbon Molecules after Electron Impact in Plasma

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(12), P. 3404 - 3411

Published: March 19, 2024

The process of dissociation for two hydrofluorocarbon molecules in low triplet states excited by electron impact plasma is investigated ab initio molecular dynamics (AIMD). interest the hydrofluorocarbons motivated their role etching microelectronic technologies. Dissociation very fast, and reaction products can be predicted. In this work, it was found that higher relax into lowest state within a few femtoseconds due to nonadiabatic dynamics, such simplest MD on seems give reasonable estimate channels branching ratios. We provide evidence existence simple rules states. For with double bond, bonds adjacent bond dissociate faster than other bonds.

Language: Английский

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Twisting Aromaticity and Photoinduced Dynamics in Hexapole Helicenes

The Journal of Physical Chemistry Letters, Journal Year: 2023, Volume and Issue: 14(45), P. 10145 - 10150

Published: Nov. 4, 2023

Curved aromatic molecules are attractive electronic materials, where an additional internal strain uniquely modifies their structure, aromaticity, dynamics, and optical properties. Helicenes examples of such twisted conjugated systems. Herein, we analyze the photoinduced dynamics in different stereoisomers a hexapole helicene by using nonadiabatic excited-state molecular simulations. We explore how changes symmetry structural distortion modulate intramolecular energy redistribution. find that distinct helical assembly leads to rigid distorted structures turn impact nonradiative relaxation ultimately formation self-trapped exciton. Subsequently, value twisting angles relative central triphenylene core structure controls global aromaticity localization during conversion process. Our work sheds light on future synthesis novel curved compounds can be directed attain specific desired properties through modulation aromaticity.

Language: Английский

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