Here we report the synthesis of two polyhelicene frameworks consisting, from end-to-end, 18 and 24 fused benzene rings. The latter exhibits largest electronic circular dichroism in visible spectrum any molecule. These shape-persistent helical nanoribbons incorporate multiple helicenes, a class contorted polycyclic aromatic molecules consisting ortho-annulated conjugated, chiral have interesting chemical, biological, chiroptical properties; however, there are very few helicenes with...

Abstract Establishing design principles to engineer molecules that exhibit strong circularly polarized luminescence (CPL)‐brightness across the UV, visible and NIR spectral range remains an unsolved challenge. To achieve a large CPL‐brightness, main difficulty is optimize dissymmetry factor g lum . Herein described discovery multi‐helicene system based on series of annulated [6]helicenes perylenediimides, exhibits larger‐than‐linear amplification with helicene length. Large enhanced...

We present a general mixed quantum classical method that couples molecular dynamics (MD) and vibronic models to compute the shape of electronic spectra flexible molecules in condensed phase without, principle, any phenomenological broadening. It is based on partition nuclear motions solute + solvent system "soft" "stiff" vibrational modes an adiabatic hypothesis assumes stiff are much faster than soft ones. In this framework, spectrum rigorously expressed as conformational integral along...

In this contribution we present a mixed quantum-classical dynamical approach for the computation of vibronic absorption spectra molecular aggregates and their nonadiabatic dynamics, taking into account coupling between local excitations (LE) charge-transfer (CT) states. The is based on an adiabatic (Ad) separation soft degrees freedom (DoFs) system stiff vibrations, which are described by quantum dynamics (QD) wave packets (WPs) moving coupled potential energy surfaces (PESs) LE CT These...

We have recently proposed a protocol for Quantum Dynamics (QD) calculations, which is based on parameterisation of Linear Vibronic Coupling (LVC) Hamiltonians with Time Dependent (TD) Density Functional Theory (TD-DFT), and exploits the latest developments in multiconfigurational TD-Hartree methods an effective wave packet propagation. In this contribution we explore potentialities approach to compute nonadiabatic vibronic spectra ultrafast dynamics, by applying it five nucleobases present...

We present an accurate and efficient approach to computing the linear nonlinear optical spectroscopy of a closed quantum system subject impulsive interactions with incident electromagnetic field. It incorporates effect ultrafast nonadiabatic dynamics by means explicit numerical propagation nuclear wave packet. The fundamental expressions for evaluation first- higher-order response functions are recast in general form that can be used any code capable overlap packets evolving different...

Hexahelicene is a prototype of an extended π-conjugated system with axial chirality. Its absorption (ABS) and electronic circular dichroism (ECD) spectra show vibronic features strong nonadiabatic effects, challenging currently available computational methods. Here, we compute the ABS ECD hexahelicene in full energy range, covering ∼2 eV 14–18 coupled states, including all relevant nuclear coordinates. To this end, exploit recently proposed protocol that uses time-dependent density...

With this work, we present a protocol for the parameterization of Linear Vibronic Coupling (LVC) Hamiltonian quantum dynamics using highly accurate multiconfigurational electronic structure methods such as RASPT2/RASSCF, combined with maximum-overlap diabatization technique. Our approach is fully portable and can be applied to many medium-size rigid molecules whose excited state requires description. We our model discuss details calculations needed parameterization, analyzing critical...

Molecules with a large chiroptic response in the visible range are key design of new efficient chiral optoelectronic devices. It has recently been shown that NP3H, helicene-based nanoribbon three perylene diimides connected by two naphthalene units, exhibits huge amplification electronic circular dichroism at 400 nm respect to NPDH, its analogue only bridged single naphthalene. Here we show time-dependent density functional theory can reproduce this experimental feature, attributing it...

Photoexcitation of 4-methoxyphenyl azide at 266 nm yields triplet nitrene after decaying through an intersystem crossing (<bold>ISC1</bold>, 2¹A′/2³A′′) in a first step followed by internal conversion (<bold>CI2</bold>, 2³A′′/1³A′′).

The hydrophilic/hydrophobic ratio and the number of water molecules released during self-assembly N -PBIs 1–4 condition enthalpic entropic contributions associated with these dyes.

The estimation of electronic couplings between diabatic states is crucial for the comprehension electron transfer phenomena molecular systems. Therefore, development efficient approximations that enable a very fast, yet accurate, an important research goal in context organic semiconductors. most popular methods (diabatization schemes, projection approximations, or using fragment orbitals) usually involve use structure calculations and can be computationally prohibitive if large number...

Abstract Several theoretical studies have proposed strategies to generate helical molecular orbitals (Hel‐MOs) in [ n ]cumulenes and oligoynes. While chiral even‐[ ] cumulenes feature Hel‐MOs, odd‐[ may also present them if the terminal groups lie different planes. However, systems been either experimentally unfeasible or resulted opposite pseudo‐degenerated Hel‐MOs. We hereby demonstrate introduction of a remarkable energy difference between twist by fixing torsion angle butadiyne...

We report a computational study on vibronic effects in the spectroscopy, photoinduced processes and decay back to ground state of aza[7]helicene, helicene with an unusually high fluorescence quantum yield (QY = 0.39).

The effect of adsorbate concentration on the potential dependent SERS spectra p-aminothiophenol (pATP) recorded a silver electrode has been studied using NaClO4 as electrolyte. Multiconfigurational second-order perturbation calculations (MS-CASPT2) have performed in order to help analysis experimental results by computing resonance Raman selected structural models metal–adsorbate surface complex. In avoid far possible any photochemical reaction, long wavelength exciting line 785 nm is used...

Vibrational wavenumbers of pyridine adsorbed on a silver electrode have been correlated to the calculated ones from different theoretical approaches based DFT methods. The vibrational tuning caused by potential has simulated means pyridine-silver clusters with densities charge or, alternatively, under applied external electric fields. Both methodologies predict correctly qualitative red-shift at negative potentials. As result, harmonic frequency calculations performed B3LYP/LanL2DZ level...

The striking SERS enhancement of the out-of-plane 16b mode pyridazine is due to resonant metal-to-molecule CT processes and not planar orientation adsorbate.

This work describes the crucial effect that optical purity and substitution pattern exert on formation mechanism stability of columnar polymers formed from self-assembly bowl-shaped subphthalocyanines.

Manufacturing process of Lithium-ion battery electrode has a direct impact on the resulting practical properties cell such as durability, safety and overall performance. In this scenario, together with experimental efforts to understand correlation between manufacturing parameters final performance, computational tools have shown potential produce insights interdependencies. The ARTISTIC initiative [1] pioneered development series 3D-resolved physics-based models describing each step...

We present a computational model for electrochemical surface-enhanced Raman scattering (EC-SERS). The surface excess of charge induced by the electrode potential (Vel) was introduced applying an external electric field to set clusters [Agn]q with (n, q) (19, ±1) or (20, 0) on which molecule adsorbs. Using DFT/TD-DFT calculations, these metal-molecule complexes were classified adsorbate partial charge, and main Vel-dependent properties simultaneously studied aid vibronic resonance...

A quantum-classical protocol that incorporates Jahn-Teller vibronic coupling effects and cluster analysis of molecular dynamics simulations is reported, providing a tool for absorption spectra ultrafast nonadiabatic in large photosystems undergoing aggregation solution. Employing zinc phthalocyanine dyes as target systems, we demonstrated the proposed provided fundamental information on vibronic, electronic couplings thermal dynamical mostly contribute to lineshape fluorescence quenching...

The effect of applied electric potentials and excitation wavelengths (785, 532, 473 nm) on the Surface-Enhanced Raman scattering (SERS) 2,2′-bipyridine (2,2′-bpy) adsorbed a silver electrode has been analyzed basis charge transfer (CT) resonance mechanism. DFT/TD-DFT calculations performed for simple model surface complex (Ag2-2,2′-bpy) point out that 2,2′-bpy preferably adsorbs through both nitrogen atoms in cis-conformation with edge-on orientation. calculated spectra two first bright...

Abstract We extend a recently proposed mixed quantum/classical method for computing the vibronic electronic circular dichroism (ECD) spectrum of molecules with different conformers, to cases where more than one hindered rotation is present. The generalizes standard procedure, based on simple Boltzmann average spectra stable and includes contribution structures that sample all accessible conformational space. It applied simulation ECD ( S )‐2,2,2‐trifluoroanthrylethanol, molecule easily...