Krypton-methanol spectroscopic study: Assessment of the complexation dynamics and the role of the van der Waals interaction.

The Kr-CHOH (Krypton-Methanol) system has several technological applications, such as the determination of diffusivity coefficients, their use in the development of detectors and combustion techniques among others. We report an extensive theoretical study concerning the stability of such complex. A mix between molecular dynamics, electronic structure calculations and solution of the nuclear Schrodinger equation lead to investigation of spectroscopic constants, lifetime of the complex and its Quantum Theory Atom in Molecules (QTAIM) properties.

Optical properties of P3HT and N2200 polymers: a performance study of an optimally tuned DFT functional.

The optical properties of systems composed of the polymers PolyeraActivInk™ N2200 and P3HT are experimentally and theoretically investigated using UV-Vis spectroscopy and time-dependent density functional theory calculations, respectively. From a theoretical point of view, we carried out an analysis considering several functionals and model oligomers of different sizes to mimic the polymers. As our studies were performed with and without solvents, a first important result regards the fact that, by considering solvent effects, a better agreement between theoretical and experimental results could be achieved.

Experimental and theoretical description of the optical properties of Myrcia sylvatica essential oil.

We present an extensive study of the optical properties of Myrcia sylvatica essential oil with the goal of investigating the suitability of its material system for uses in organic photovoltaics. The methods of extraction, experimental analysis, and theoretical modeling are described in detail. The precise composition of the oil in our samples is determined via gas chromatography, mass spectrometry, and X-ray scattering techniques.

Optical and electronic structure description of metal-doped phthalocyanines.

Phthalocyanines represent a crucial class of organic compounds with high technological appeal. By doping the center of these systems with metals, one obtains the so-called metal-phthalocyanines, whose property of being an effective electron donor allows for potentially interesting uses in organic electronics. In this sense, investigating optical and electronic structure changes in the phthalocyanine profiles in the presence of different metals is of fundamental importance for evaluating the appropriateness of the resulting system as far as these uses are concerned.

Combined UMC- DFT prediction of electron-hole coupling in unit cells of pentacene crystals.

Pentacene is an organic semiconductor that draws special attention from the scientific community due to the high mobility of its charge carriers. As electron-hole interactions are important aspects in the regard of such property, a computationally inexpensive method to predict the coupling between these quasi-particles is highly desired. In this work, we propose a hybrid methodology of combining Uncoupled Monte Carlo Simulations (UMC) and Density functional Theory (DFT) methodologies to obtain a good compromise between computational feasibility and accuracy.

Optimally tuned functionals improving the description of optical and electronic properties of the phthalocyanine molecule.

By means of Density functional theory and time-dependent density functional theory calculations, we present a comprehensive investigation on the influence of different functional schemes on electronic and optical properties of the phthalocyanine molecule. By carrying out our own tuning on the OT-LC-BLYP/6-31G(d,p) functional, we show that such a procedure is fundamental to accurately match experimental results. We compare our results to several others available in the literature, including the B3LYP/6-31+G(d,p) set, which is commonly portrayed as the best combination in order to obtain a good description of the band gap.

Modeling optical properties of polymer-solvent complexes: the chloroform influence on the P3HT and N2200 absorption spectra.

The optical properties of polymer/solvent systems composed by the polymers P3HT and PolyeraActivInk N2200 under the present of chloroform as solvent are experimentally and theoretically investigated using UV-Vis spectroscopy, molecular dynamics (MD), and density functional theory (DFT) calculations. The study is focused on obtaining the theoretical methodologies that properly describes the experimentally obtained absorption spectra of polymer-solvent complexes. In order to investigate the solvent influence, two different approaches are taken into account: the solvation shell method (SSM) and the polarizable continuum model (PCM).

The H + Li2 bimolecular exchange reaction: dynamical and kinetical properties at J = 0.

For the first time in the literature, rigorous time-independent quantum scattering formalism was applied, by means of the ABC program, to the H + Li(2) → LiH + Li reaction. The state-to-state probabilities as a function of the total energy have been computed at zero total angular momentum (J = 0) allowing us to evaluate the effect of vibrational/rotational excitation on the reaction promotion/inhibition, the energetic distribution of products, and the temperature dependence of the J-shifting thermal rate coefficients.