After photoexcitation, energy absorbed by a molecule can be transferred efficiently over distance of up to several tens angstroms another the process resonance transfer, RET (also commonly known as electronic EET). Examples where is observed include natural and artificial antennae for capture conversion light, amplification fluorescence-based sensors, optimization organic light-emitting diodes, measurement structure in biological systems (FRET). Förster theory has proven very successful at...

We present a combined quantum mechanics and molecular (QM/MM) method to study electronic energy transfer (EET) in condensed phases. The introduces mechanically based linear response (LR) scheme describe both chromophore excitations couplings, while the environment is described through classical polarizable force field. Explicit treatment of solvent polarization key aspect model, as this allows account screening effects coupling. tested on model perylene diimide (PDI) dimer water solution....

In a recent Account, Cramer and Truhlar presented comparison between the SM8 method standard versions of other continuum solvation models implemented in widely available quantum mechanical programs. that model was found to lead "considerably smaller errors for aqueous nonaqueous free energies neutrals, cations, anions, with particularly good performance data". Here, we demonstrate competing methods are indeed as accurate method, if they applied same rigor.

The way that solvent (or host medium) modifies the rate of electronic energy transfer (EET) has eluded researchers for decades. By applying quantum chemical methods account (in general any medium including liquid, solid, or protein, etc.) responds to interaction between transition densities, we quantify screening. We find it attains a striking exponential attenuation at separations less than about 20 A, thus interpolating limits no apparent screening and significant EET rate. That...

In photosynthesis, special antenna proteins that contain multiple light-absorbing molecules (chromophores) are able to capture sunlight and transfer the excitation energy reaction centers with almost 100% quantum efficiencies. The critical role of protein scaffold in holding appropriate arrangement chromophores is well established can be intuitively understood given need keep optimal dipole−dipole interactions between energy-transferring chromophores, as described by Förster theory more than...

This paper presents a quantum-mechanical study of electronic energy transfer (EET) coupling on over 100 pairs chromophores taken from photosynthetic light-harvesting antenna proteins. Solvation effects due to the protein, intrinsic waters, and surrounding medium are analyzed in terms screening reaction field contributions using model developed recently that combines linear response approach with polarizable continuum (PCM). We find EET interactions is quite insensitive treatment adopted. In...

Abstract In pursuit of a better understanding how electronic excitation migrates within complex structures, the concept resonance energy transfer is being extended and deployed in wide range applications. Utilizing knowledge quantum interactions that operate natural photosynthetic systems, wide‐ranging molecular solid‐state materials are explored cause more efficient solar harvesting, while advances theory paving way for development application fundamentally new mechanisms. this review, an...

Excitation energy transfer involving semiconductor quantum dots (QDs) has received increased attention in recent years because their properties, such as high photostability and size-tunable optical have made QDs attractive Förster resonant (FRET) probes or sensors. An intriguing question FRET studies been whether the dipole approximation, commonly used to predict electronic coupling, is sufficiently accurate. Accurate estimates of couplings between two 3.9 nm CdSe a QD chlorophyll molecule...

The nature of the coupling photoexcited chromophore with environment in a prototypical system like green fluorescent protein (GFP) is to date not understood, and its description still defies state-of-the-art multiscale approaches. To identify which theoretical framework chromophore-protein complex can realistically capture essence, we employ here variety electronic-structure methods, namely, time-dependent density functional theory (TD-DFT), multireference perturbation (NEVPT2 CASPT2),...

Abstract We report a combined molecular dynamics and quantum mechanics (QM)/molecular (MM) analysis of the excitonic properties Fenna–Matthews–Olson (FMO) protein by using polarizable MM model with time‐dependent density functional theory description. Overall, our results indicate that structural fluctuations, electrostatic interactions, short‐range effects can significantly modulate Hamiltonian parameters (site energies couplings). find specific interactions axial ligand hydrogen‐bonded...

Over the past decade, both experimentalists and theorists have worked to develop methods describe pigment-protein coupling in photosynthetic light-harvesting complexes order understand molecular basis of quantum coherence effects observed photosynthesis. Here we present an improved strategy based on combination mechanics/molecular mechanics (QM/MM) dynamics (MD) simulations excited-state calculations predict spectral density electronic-vibrational coupling. We study water-soluble...

Abstract Amyloids are characterized by their capacity to bind Congo red (CR), one of the most used amyloid‐specific dyes. The structural features CR binding were unknown for years, mainly because lack amyloid structures solved at high resolution. In last few solid‐state NMR spectroscopy enabled determination amyloids, such as HET‐s prion forming domain (HET‐s PFD), which also has recently been determine amyloid–CR interface atomic Herein, we combine spectroscopic data with molecular docking,...

Abstract This study reports the parametrization of HF/6‐31G(d) version MST continuum model for n ‐octanol. Following our previous studies related to water, chloroform, and carbon tetrachloride, a detailed exploration definition solute/solvent interface has been performed. To this end, we have exploited results obtained from free energy calculations coupled Monte Carlo simulations, those derived QM/MM analysis solvent‐induced dipoles selected solutes. The atomic hardness parameters determined...

This paper presents a quantum-mechanical study of the intramolecular excitation energy transfer (EET) coupling in naphthalene-bridge-naphthalene systems gas phase and solution. ZINDO TDDFT response schemes are compared using both an exact approximate The solution based on perturbative approach uses single chromophore properties to reconstruct real system thus neglecting possible through-bond effects which conversely accounted for comparison results two approaches with experiments allows...

We present a QM/QM approach for the calculation of solvent screening effects on excitation-energy transfer (EET) couplings. The method employs subsystem time-dependent density-functional theory formalism [J. Chem. Phys. 2007, 126, 134116] and explicitly includes excited states to account environmental response. It is investigated how efficiency these calculations can be enhanced in order treat systems with very large solvation shells while fully including In particular, we introduce...

Recent studies have unveiled the similar nature of solvent (screening) effects and bridge-mediated contributions to electronic energy transfer, both related bridge/solvent polarizability properties. Here, we exploit similarity such develop a fully polarizable mixed QM/discrete/continuum model aimed at studying transfer processes in supramolecular systems. In model, definition three regions is completely flexible allows us explore possibility describe by using MM description linker. addition,...

We present an evaluation of the performance various single-reference QM methods for prediction relative site energies and transition moments Q bands in bacteriochlorophyll a (BChl a) pigments Fenna-Matthew-Olson (FMO) complex. examine merits ZINDO, CIS, TD-DFT (with functionals PBE, BLYP, PBE0, B3LYP, CAM-B3LYP) RI-CC2 reproducing variations across that occur as consequence geometrical electrostatic effects FMO complex by comparison to DFT-BHLYP/MRCI. find these are near-multiconfigurational...

We present the mathematical derivation and computational implementation of analytical geometry derivatives for a polarizable QM/MM model (QM/MMPol). In adopted QM/MMPol model, focused part is treated at QM level theory, while remaining (the environment) described classically as set fixed charges induced dipoles. The performed within ONIOM procedure, resulting in embedding scheme, which can be applied to solvated embedded systems combined with different force fields available literature. Two...

Abstract We describe the development, implementation, and application of a polarizable QM/MM strategy, based on AMOEBA force field, for calculating molecular properties performing dynamics systems embedded in complex matrices. show that is well‐understood, mature technology can be deployed using state‐of‐the‐art implementation combines efficient numerical methods linear scaling techniques. Thanks to these advances availability parameters wide manifold QM/AMOEBA used advanced production...

ABSTRACT Continuum solvation models such as the polarizable continuum model and conductor‐like screening are widely used in quantum chemistry, but their application to large biosystems is hampered by computational cost. Here, we report parametrization of Miertus–Scrocco–Tomasi (MST) for prediction hydration free energies neutral ionic molecules based on domain decomposition formulation COSMO (ddCOSMO), which allows a drastic reduction cost several orders magnitude. We also introduce...

Incorporation of environment and vibronic effects in simulations optical spectra excited state dynamics is commonly done by combining molecular with calculations, which allows to estimate the spectral density describing frequency-dependent system-bath coupling strength. The need for efficient sampling, however, usually leads adoption classical force fields despite well-known inaccuracies due mismatch method. Here, we present a multiscale strategy that overcomes this limitation EMLE based on...