STAMCA Bypass inside Carotid Stenosis soon after Radiosurgery regarding Spacious Nasal Meningioma

Electronic correlation energies from the random-phase approximation converge slowly with respect to the plane wave basis set size. We study the conditions under which a short-range local density functional can be used to account for the basis set incompleteness error. Furthermore, we propose a one-shot extrapolation scheme based on the Lindhard response function of the homogeneous electron gas. The different basis set correction methods are used to calculate equilibrium lattice constants for prototypical solids of different bonding types.In this work, the oxygen reduction reaction (ORR) on tellurium-modified Pt(111) surfaces has been studied. Adsorption of Te adatoms on Pt(111) progressively shifts toward less positive values of both the ORR reaction onset and the half-wave potential in 0.1M HClO4 for 0 0.25, the ORR activity increases relative to the one at θTe less then 0.25, but remains lower than that on clean Pt(111). Results were analyzed in light of simulations of kinetic currents as a function of θTe, calculated by employing a simple mean field model including both site blocking and electronic effects. Inside this framework, experimental data are best explained by considering that oxygenated Te species inhibit the ORR by either negatively modifying adsorption energies of reaction intermediates or combined site-blocking and electronic effects. A redox ORR catalysis due to redox properties of Te adatoms is discarded. Contrarily, in 0.05M H2SO4, a positive catalytic effect has been found, interpreted in terms of a competitive adsorption-desorption mechanism involving the replacement of adsorbed sulfate by Te adatoms. On the other hand, despite the strong site-blocking effect on Hads and OHads adsorption by Te adatoms, it appears that the reduced Te-Pt(111) adlayer does not inhibit the reaction, suggesting different active sites for Hads and OHads adsorption and for the rate-determining step of the ORR mechanism.Predicting accurate nuclear magnetic resonance chemical shieldings relies upon cancellation of different types of errors between the theoretically calculated shielding constant of the analyte of interest and the reference. Often, the intrinsic error in computed shieldings due to basis sets, approximations in the Hamiltonian, description of the wave function, and dynamic effects is nearly identical between the analyte and reference, yet if the electronic structure or sensitivity to local environment differs dramatically, this cannot be taken for granted. Detailed prior work has examined the octahedral trivalent cation Al(H2O)6 3+, accounting for ab initio intrinsic errors. However, the use of this species as a reference for the chemically distinct tetrahedral anion Al(OH)4 - requires an understanding of how these errors cancel in order to define the limits of accurately predicting Al27 chemical shielding in Al(OH)4 -. In this work, we estimate the absolute shielding of the Al27 nucleus in Al(OH)4 - at the coupled cluster level (515.1 ± 5.3 ppm). Shielding sensitivity to the choice of method approximation and atomic basis sets used has been evaluated. Solvent and thermal effects are assessed through ensemble averaging techniques using ab initio molecular dynamics. The contribution of each type of intrinsic error is assessed for the Al(H2O)6 3+ and Al(OH)4 - ions, revealing significant differences that fundamentally hamper the ability to accurately calculate the Al27 chemical shift of Al(OH)4 - from first principles.We present a method for the generation of points in space needed to create training data for fitting of nonlinear parametric models. This method uses statistical information extracted from an initial fit on a sparse grid to select optimal grid points in an iterative manner and is, therefore, called the iterative variance minimizing grid approach. We demonstrate the method in the case of six-dimensional intermolecular potential energy surfaces (PESs) fitted to ab initio computed interaction energies. The number of required grid points is reduced by roughly a factor of two in comparison to alternative systematic sampling methods. The method is not limited to fitting PESs and can be applied to any cases of fitting parametric models where data points may be chosen freely but are expensive to obtain.We have developed an accurate and efficient method for molecular dynamics simulations of charged particles confined by planar dielectric interfaces. The algorithm combines the image-charge method for near field with the harmonic surface mapping, which converts the contribution of infinite far-field charges into a finite number of charges on an auxiliary spherical surface. We approximate the electrostatic potential of far-field charges via spherical harmonic expansion and determine the coefficients by fitting the Dirichlet-to-Neumann boundary condition, which only requires the potential within the simulation cell. Instead of performing the direct evaluation of spherical harmonic series expansion, we use Green's second identity to transform the series expansion into a spherical integral, which can be accurately represented by discrete charges on the sphere. Therefore, the fast multipole method can be readily employed to sum over all charges within and on the sphere, achieving truly linear O(N) complexity. Our algorithm can be applied to a broad range of charged complex fluids under dielectric confinement.The excited state photodynamics of isolated benzene have been studied in the nanosecond range by two-step photoionization through various vibrations of the lowest singlet state, with imaging photoelectron spectroscopy detection. Photoelectron spectra are measured as a function of pump-probe delay time, and their time evolution is successfully compared to a biexponential decay function without regard to a particular kinetic model. The only reasonable kinetic model with only two exponentials is the one that involves an intersystem crossing from S1 to T1, although that model has previously been called into question by high-resolution studies that failed to find any singlet-triplet perturbations in Zeeman studies of the S1 spectrum. this website That contradiction remains unresolved.