Photo-induced processes are fundamental in nature but accurate simulations of their dynamics seriously limited by the cost underlying quantum chemical calculations, hampering application for long time scales. Here we introduce a method based on machine learning to overcome this bottleneck and enable photodynamics nanosecond scales, which otherwise out reach with contemporary approaches. Instead expensive chemistry during molecular simulations, use deep neural networks learn relationship...

We report an implementation of the linear vibronic coupling (LVC) model within surface hopping dynamics approach and present utilities for parameterizing this in a blackbox fashion. This results extremely efficient method to obtain qualitative even semi-quantitative information about photodynamical behavior molecule, provides new route toward benchmarking computations. The merits applicability are demonstrated number applications. First, is applied SO2 molecule showing that it possible...

The quality of molecular dynamics simulations strongly depends on the accuracy underlying force fields (FFs) that determine all intra- and intermolecular interactions system. Commonly, transferable FF parameters are determined based a representative set small molecules. However, such an approach sacrifices in favor generality. In this work, open-source automated toolkit named Q-Force is presented, which augments these FFs with molecule-specific bonded atomic charges derived from quantum...

We report the development and implementation of an exciton approach that allows ab initio nonadiabatic dynamics simulations electronic excitation energy transfer in multichromophoric systems. For dynamics, a trajectory-based strategy is used within surface hopping formulation. The features consistent hybrid formulation construction potential surfaces gradients by combining quantum mechanics molecular electrostatic embedding scheme. As application, study dyad consisting covalently bound...

The accurate description of large molecular systems in complex environments remains an ongoing challenge for the field computational chemistry. This problem is even more pronounced photoinduced processes, as multiple excited electronic states and their corresponding nonadiabatic couplings must be taken into account. Multiscale approaches such hybrid quantum mechanics/molecular mechanics (QM/MM) offer a balanced compromise between accuracy burden. Here, we introduce open-source software...

Quantum-classical methods for nonadiabatic molecular dynamics, based on the Mayer-Miller-Stock-Thoss mapping, are implemented in open source computer package PySurf. This complements implementation of surface hopping approaches performed previous works, and leads to a unified code that allows dynamics simulations using various mapping (Ehrenfest linearized semiclassical initial value representation, Poisson-bracket equation, “unity” approach indentity operator, spin method) as well different...

The photodynamics and UV spectroscopy of decatetraene following excitation to the bright 1Bu state are studied theoretically, based on ab initio computations underlying potential energy (PE) surfaces. Both photophysical photochemical aspects investigated. former involves smaller amplitude displacements, – in addition determining multidimensional PE surfaces also a quantal treatment ensuing nuclear dynamics. inclusion 1Bu–2Ag vibronic interaction allows compute vibrational structure 1Ag–1Bu...

The inclusion of solvent effects in the calculation excited states is vital to obtain reliable absorption spectra and density solvated chromophores. Here we analyze performance three classical approaches describe aqueous pyridine, tropone, tropothione. Specifically, compare results obtained from quantum mechanics/polarizable continuum model (QM/PCM) versus mechanics/molecular mechanics (QM/MM) its electrostatic-embedding (QM/MMee) polarizable-embedding (QM/MMpol) fashions, against full-QM...

We present a computational study of sub-picosecond nonadiabatic dynamics in rhenium complex coupled electronically to tryptophan (Trp) side chain

Charge and structural relaxation of electronically excited states in embedded systems are strongly affected by the environment. It is known that largest part environment effects comes from electrostatics. However, polarization can also play a role tuning electronic geometrical properties states, finally modifying fluorescence. Here we present formulation analytical excited-state gradients within polarizable QM/MM approach their implementation ONIOM framework. A time-dependent DFT level...

Abstract In a systematic study of the Au‐catalyzed reaction o ‐alkynylphenols with aryldiazonium salts, we find that essentially same conditions lead to change in mechanism when light source is applied. If carried out at room temperature using Au I catalyst, diazonium salt undergoes electrophilic deauration vinyl intermediate and provides access substituted azobenzofurans. mixture irradiated blue LED light, C−C bond formation due N 2 ‐extrusion from realized selectively, starting materials...

Photoinduced nonadiabatic processes play a crucial role in wide range of disciplines, from fundamental steps biology to modern applications advanced materials science. A theoretical understanding these is highly desirable, and trajectory surface hopping (TSH) has proven be well-suited framework for systems. In this work, we present comprehensive comparison between two TSH algorithms, the conventional Tully's fewest switches (FSSH) scheme Landau-Zener (LZSH), study photoinduced ring-opening...

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The greatest restriction to the theoretical study of dynamics photoinduced processes is computationally expensive electronic structure calculations. Machine learning algorithms have potential reduce number these computations significantly. Here, PySurf introduced as an innovative code framework, which specifically designed for rapid prototyping and development tasks data science applications in computational chemistry. It comes with powerful Plugin Workflow engines, allows intuitive...

We present an efficient set of methods for propagating excited-state dynamics involving a large number configuration interaction singles (CIS) or Tamm-Dancoff approximation (TDA) single-reference excited states. Specifically, (i) following Head-Gordon et al., we implement exact evaluation the overlap singly-excited CIS/TDA electronic states at different nuclear geometries using biorthogonal basis and (ii) employ unified protocol choosing correct phase each adiabat geometry. For many-electron...

Photoinduced processes play a crucial role in multitude of important molecular phenomena. Accurately modeling these an environment other than vacuum requires detailed description the electronic states involved as well how energy flows are coupled to surroundings. Nonadiabatic effects must also be included order describe exchange between and nuclear degrees freedom correctly. In this work, we revisit ring-opening reaction 1,3-cylohexadiene (CHD) solvent environment. Using our newly developed...

Abstract The multi-state vibronic interactions in the benzene radical cation are investigated theoretically, based on an ab initio quantum dynamical approach. three lowest doubly degenerate and two non-degenerate electronic states included, amounting to eight component 28 vibrational degrees of freedom. multi-mode Jahn-Teller as well pseudo effects included equal footing. This becomes possible by employing Multiconfigurational Time-Dependent Hartree Method its multi-layer extension for...

An enantioconvergent palladium-catalyzed Negishi cross-coupling with racemic secondary organozinc reagents has been developed, enabling access to enantioenriched 1,1-diarylalkane motifs in high yields and enantioselectivities. Computational data indicates that the racemization of compounds most likely occurs through a bridged bimolecular mechanism.

We present a new software package called M-Chem that is designed from scratch in C++ and parallelized on shared-memory multi-core architectures to facilitate efficient molecular simulations. Currently, fast dynamics (MD) engine supports the evaluation of energies forces two-body many-body all-atom potentials, reactive force fields, coarse-grained models, combined quantum mechanics (QM/MM) external drivers machine learning, augmented by algorithms are focused gains computational simulation...

The UV absorption spectrum of all-trans-octatetraene is reinvestigated theoretically, focussing on the strongly dipole-allowed 1Ag–1Bu transition. dynamical calculations rely ab initio multistate CASPT2 (MS-CASPT2) computations underlying potential energy surfaces and coupling elements, multiconfiguration time-dependent Hartree (MCTDH) method for solving Schrödinger equation nuclear motion. vibronic structure band near 2700 Å well reproduced, better than ever before by a purely approach. C–C...

Abstract Eine enantiokonvergente, palladiumkatalysierte Negishi‐Kreuzkupplung mit racemischen sekundären Organozink‐Reagenzien wurde entwickelt, die den Zugang zu enantioangereicherten 1,1‐Diarylalkan‐Motiven in hohen Ausbeuten und Enantioselektivitäten ermöglicht. Berechnungsdaten deuten darauf hin, dass Racemisierung von Organozink‐Verbindungen höchstwahrscheinlich durch einen gebrückten bimolekularen Mechanismus erfolgt.

Abstract We unveil in this work the main factors that govern turn‐on/off fluorescence of a Se‐modified uracil probe at ribosomal RNA A‐site. Whereas constraint into an “in‐plane” conformation two rings fluorophore is driver for observed turn‐on emission presence antibiotic paromomycin, electrostatics environment plays minor role during process. Our computational strategy clearly indicates that, absence prefers conformations show dark S 1 electronic state with participation nπ* transition...