Prediction Challenge: Simulating Rydberg photoexcited cyclobutanone with surface hopping dynamics based on different electronic structure methods

The Journal of Chemical Physics, Год журнала: 2024, Номер 160(15)

Опубликована: Апрель 16, 2024

This research examines the nonadiabatic dynamics of cyclobutanone after excitation into n → 3s Rydberg S2 state. It stems from our contribution to Special Topic Journal Chemical Physics test predictive capability computational chemistry against unseen experimental data. Decoherence-corrected fewest-switches surface hopping was used simulate with full and approximated couplings. Several simulation sets were computed different electronic structure methods, including a multiconfigurational wavefunction [multiconfigurational self-consistent field (MCSCF)] specially built describe dissociative channels, multireference semiempirical approach, time-dependent density functional theory, algebraic diagrammatic construction, coupled cluster. MCSCF predicts slow deactivation state (10 ps), followed by an ultrafast population transfer S1 S0 (<100 fs). CO elimination (C3 channel) dominates over C2H4 formation (C2 channel). These findings radically differ other which predicted lifetimes 10-250 times shorter C2 channel predominance. results suggest that routine methods may hold low power for outcome dynamics.

Язык: Английский

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MLatom Software Ecosystem for Surface Hopping Dynamics in Python with Quantum Mechanical and Machine Learning Methods

Journal of Chemical Theory and Computation, Год журнала: 2024, Номер 20(12), С. 5043 - 5057

Опубликована: Июнь 5, 2024

We present an open-source MLatom@XACS software ecosystem for on-the-fly surface hopping nonadiabatic dynamics based on the Landau–Zener–Belyaev–Lebedev algorithm. The can be performed via Python API with a wide range of quantum mechanical (QM) and machine learning (ML) methods, including ab initio QM (CASSCF ADC(2)), semiempirical methods (e.g., AM1, PM3, OMx, ODMx), many types ML potentials KREG, ANI, MACE). Combinations also used. While user build their own combinations, we provide AIQM1, which is Δ-learning used out-of-the-box. showcase how AIQM1 reproduces isomerization yield trans-azobenzene at low cost. example scripts that, in dozens lines, enable to obtain final population plots by simply providing initial geometry molecule. Thus, those perform optimization, normal mode calculations, condition sampling, parallel trajectories propagation, analysis, result plotting. Given capabilities MLatom training different models, this seamlessly integrated into protocols building models dynamics. In future, deeper more efficient integration Newton-X will vast functionalities dynamics, such as fewest-switches hopping, facilitate similar workflows API.

Язык: Английский

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A MASH simulation of the photoexcited dynamics of cyclobutanone

The Journal of Chemical Physics, Год журнала: 2024, Номер 160(17)

Опубликована: Май 2, 2024

In response to a community prediction challenge, we simulate the nonadiabatic dynamics of cyclobutanone using mapping approach surface hopping (MASH). We consider first 500 fs relaxation following photoexcitation S2 state and predict corresponding time-resolved electron-diffraction signal that will be measured by planned experiment. 397 ab initio trajectories were obtained on fly with state-averaged complete active space self-consistent field (12,11) space. To obtain an estimate potential systematic error, 198 calculated aug-cc-pVDZ basis set 199 6-31+G* set. MASH is recently proposed independent trajectory method for simulating dynamics, originally derived two-state problems. As there are three relevant electronic states in this system, used newly developed multi-state generalization simulation: uncoupled spheres (unSMASH). This study, therefore, serves both as investigation photodissociation cyclobutanone, also demonstration applicability unSMASH simulations. line previous experimental studies, observe simulated dominated sets dissociation products, C3H6 + CO, C2H4 C2H2O, CH2 interpret our predicted terms key features associated pathways.

Язык: 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, Год журнала: 2024, Номер 15(22), С. 5814 - 5823

Опубликована: Май 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

Язык: 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, Год журнала: 2024, Номер 20(11), С. 4396 - 4426

Опубликована: Май 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.

Язык: Английский

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ULaMDyn: Enhancing Excited-State Dynamics Analysis Through Streamlined Unsupervised Learning

Digital Discovery, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

The analysis of nonadiabatic molecular dynamics (NAMD) data presents significant challenges due to its high dimensionality and complexity. To address these issues, we introduce ULaMDyn, a Python-based, open-source package designed automate the unsupervised large datasets generated by NAMD simulations. ULaMDyn integrates seamlessly with Newton-X platform employs advanced reduction clustering techniques uncover hidden patterns in trajectories, enabling more intuitive understanding excited-state processes. Using photochemical fulvene as test case, demonstrate how efficiently identifies critical geometries transitions. offers streamlined, scalable solution for interpreting datasets. It is poised facilitate advances study across wide range systems.

Язык: Английский

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

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Март 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.

Язык: Английский

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Quantum Dynamics from Classical Trajectories

Journal of Chemical Theory and Computation, Год журнала: 2024, Номер unknown

Опубликована: Сен. 5, 2024

Nonadiabatic molecular dynamics plays an essential role in exploring the time evolution of systems. Various methods have been developed for this study, with varying accuracy and computational cost. One very successful among them is trajectory surface hopping, which propagates nuclei as classical trajectories using forces from a quantum description electrons incorporates nonadiabatic effects through stochastic state changes during each propagation. A statistical analysis ensemble independent recovers simulated system's behavior. This approach can give good results, but it known to overlook nuclear effects, leading inaccurate predictions. Here, we present (QDCT), new protocol recover wavepacket generated by hopping. In first QDCT implementation, apply results at multiple spawning level postprocessing hopping precomputed trajectories. With series examples, demonstrate QDCT's potential improve dynamics, correct decoherence diagnose problems or increase confidence results. All that comes virtually no cost since electronic calculation required.

Язык: Английский

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Legion: A Platform for Gaussian Wavepacket Nonadiabatic Dynamics

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Март 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).

Язык: Английский

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Generalization of Quantum-Trajectory Surface Hopping to Multiple Quantum States

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Март 10, 2025

In this work, we present a generalization of the quantum trajectory surface hopping (QTSH) to multiple states and its implementation in Libra package for nonadiabatic dynamics. lieu ad hoc velocity rescaling used many trajectory-based approaches, QTSH utilizes forces evolve nuclear degrees freedom continuously. It also lifts unphysical constraint enforcing total energy conservation at individual level rather conserves ensemble level. Leveraging our new multistate QTSH, perform comparative analysis method with conventional fewest switches approach. We combine decoherence corrections based on simplified decay mixing (SDM) exact factorization (XF), leading QTSH-SDM QTSH-XF schemes. Using Holstein, superexchange, phenol model Hamiltonians, assess relative accuracy resulting combined schemes reproducing branching ratios, population, coherence dynamics broad range initial conditions. observe that correction is crucial improve as well internal consistency between population from probability active state.

Язык: Английский

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