A5049181765- Spectroscopy and Quantum Chemical Studies
- Photosynthetic Processes and Mechanisms
- Photoreceptor and optogenetics research
- Photochemistry and Electron Transfer Studies
- Perovskite Materials and Applications
- Conducting polymers and applications
- Spectroscopy and Laser Applications
- Organic Electronics and Photovoltaics
- Quantum Dots Synthesis And Properties
- Plant Stress Responses and Tolerance
- Advanced Chemical Physics Studies
- Advanced Thermodynamics and Statistical Mechanics
- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Porphyrin and Phthalocyanine Chemistry
- Molecular spectroscopy and chirality
- Light effects on plants
- Quantum, superfluid, helium dynamics
- Advanced Electron Microscopy Techniques and Applications
- Chalcogenide Semiconductor Thin Films
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Thin-Film Transistor Technologies
- Quantum Electrodynamics and Casimir Effect
- Solid-state spectroscopy and crystallography
Vilnius University
2016-2025
Center for Physical Sciences and Technology
2015-2024
We propose an optimized tight-binding electron–hole model of the photosystem II (PSII) reaction center (RC). Our incorporates two charge separation pathways and spatial correlations both static disorder fast fluctuations energy levels. It captures main experimental features observed in time-resolved two-dimensional (2D) optical spectra at 77 K: peak pattern, lineshapes time traces. Analysis 2D kinetics reveals that specific regions PSII RC are sensitive to transfer states. find peripheral...
Linear absorption is the most basic optical spectroscopy technique that provides information about electronic and vibrational degrees of freedom molecular systems. In simulations lineshapes, often diagonal fluctuations are included using cumulant expansion, off-diagonal accounted for either perturbatively, or phenomenologically. The accuracy these methods limited their range validity still questionable. this work, a systematic study several such presented by comparing lineshapes with exact...
Time-resolved fluorescence spectroscopy of molecular aggregates is described using the response function theory, which incorporates exciton dynamics through nonequilibrium Green's functions. The are simulated nonperturbative density matrix allows us to describe spectral and temporal signatures various system-bath coupling regimes. We find that conventional excitonic picture eigenstates valid in Markovian regime. In non-Markovian regime, concept breaks down renormalized quantities can be...
Fluorescence concentration quenching occurs when increasing molecular of fluorophores results in a decreasing fluorescence quantum yield. Even though this phenomenon has been studied for decades, its mechanisms and signatures are not yet fully understood. The complexity the problem arises due to energy migration trapping huge networks molecules. Most available theoretical work focuses on integral quantities like yield mean excitation lifetime. In work, we present numerical study decay...
Understanding the dynamics of injected charge carriers is crucial for analysis perovskite light-emitting diode (PeLED) operation. The behavior largely dictates external quantum efficiency (EQE) roll-off at high current densities and temperature dependence EQE in PeLEDs. However, limitations such as sample capacitance circuitry hinder precise control carrier injection rates, making it challenging to directly track individual carriers. Here, we explore recombination a small-grain...
Light-harvesting in fucoxanthin-chlorophyll protein (FCP) of diatoms is performed by a cluster chromophores: chlorophylls (Chl a), c2 c2), and carotenoids fucoxanthins. It well-known that energy captured fucoxanthin transferred to Chl on subpicosecond time scale. However, the flow channel connecting remained elusive. In this study, transfer between molecules FCP complex from diatom algae C. meneghiniana at room temperature investigated using pump–probe coherent two-dimensional electronic...
Energy transfer processes and coherent phenomena in the fucoxanthin–chlorophyll protein complex, which is responsible for light harvesting function marine algae diatoms, were investigated at 77 K by using two-dimensional electronic spectroscopy. Experiments performed on femtosecond picosecond timescales led to separation of spectral dynamics, witnessing evolutions coherence population states system region Qy transitions chlorophylls a c. Analysis dynamics allowed us identify chlorophyll...
Two-dimensional electronic spectroscopy of the photosystem II core complex reveals rapid energy transfer that can be explained through excitonic-polaron formation.
Photosystem II (PSII) is the only biological system capable of splitting water to molecular oxygen. Its reaction center (RC) responsible for primary charge separation that drives oxidation reaction. In this work, we revisit spectroscopic properties PSII RC using complex time-dependent Redfield (ctR) theory optical lineshapes [A. Gelzinis et al., J. Chem. Phys. 142, 154107 (2015)]. We obtain model parameters (site energies, disorder, and reorganization energies) from fits several spectra then...
Abstract Heterogeneous organic‐inorganic halide perovskites possess inherent non‐uniformities in bandgap that are sometimes engineered and exploited on purpose, like quasi‐2D perovskites. In these systems, charge carrier excitation energy migration to lower‐bandgap sites key processes governing luminescence. The question, which of them dominates particular materials under specific experimental conditions, still remains unanswered, especially when carriers comprise excitons. this study...
In this Perspective, we demonstrate that the published FCP structures are not entirely consistent with 2D spectroscopy results for <italic>Cyclotella meneghiniana</italic>. To remedy issue, propose pigment arrangement in trimeric species.
Calculation of the equilibrium state an open quantum system interacting with a bath remains challenge to this day, mostly due huge number degrees freedom. Here, we present analytical expression for reduced density operator in terms effective Hamiltonian high temperature case. Comparing numerically exact results, show that our theory is accurate slow baths and up intermediate system-bath coupling strengths. Our results demonstrate does not depend on shape spectral regime. The key quantity...
Dynamics of excitonic polaron formation in molecular systems coupled to an overdamped bath are investigated using the Dirac-Frenkel variational principle and Davydov D1 Ansatz. Using a two-site model system we show that few qualitatively distinct relaxation regimes optically created exciton possible, depending on timescale fluctuations. A slow always leads adiabatic formation. Non-adiabatic self-trapping occurs when is strongly fast bath. Weak coupling such does not perturb picture. The...
The photosynthetic apparatus of plants is a robust self-adjustable molecular system, able to function efficiently under varying environmental conditions. Under strong sunlight, it switches into photoprotective mode avoid overexcitation by safely dissipating the excess absorbed light energy via nonphotochemical quenching (NPQ). Unfortunately, heterogeneous organization and simultaneous occurrence multiple processes within thylakoid membrane impede study natural NPQ in vivo conditions; thus,...
Abstract Charge transfer (CT) states play a key role in the functioning of organic solar cells; however, understanding mechanism by which CT dissociate efficiently into free charges remain conceptual challenge. Here, electric field dependent dynamics charge generation planar cyanine/fullerene photovoltaic cells is probed over wide temperature range using time‐resolved Stark effect experiments, transient absorption, and photocurrent measurements. Results indicate that dissociation thermalized...
Accurate simulations of open quantum system dynamics is a long standing issue in the field chemical physics. Exact methods exist, but are costly, while perturbative limited their applicability. Recently new black-box type method, called transfer tensor method (TTM), was proposed [J. Cerrillo and J. Cao, Phys. Rev. Lett. 112, 110401 (2014)]. It allows one to accurately simulate time with numerical cost solving time-convolution master equation, provided many initial evolution trajectories...
Diatoms are a group of marine algae that responsible for significant part global oxygen production. Adapted to life in an aqueous environment dominated by the blue-green light, their major light-harvesting antennae-fucoxanthin-chlorophyll protein complexes (FCPs)-exhibit different pigment compositions than plants. Despite extensive experimental studies, until recently theoretical description excitation energy dynamics these was limited lack high-resolution structural data. In this work, we...