Gilmoreengberg6394

Differing from the wetting on a flat substrate, we show that the surface composition varying with temperature leads to a distinct wetting phenomenon in porous structures. The present findings provide an alternative interpretation for complete wetting and are expected to be exploited for designing more effectively and efficiently superhydrophilic structures.First principles simulations of carbon dioxide adsorbed on the ceria (CeO2) (111) surface are discussed in terms of structural features, stability, charge transfer, and vibrational modes. For this purpose, different density functional theory methods, such as Perdew-Burke-Ernzerhof (PBE) PBE and Hubbard correction, hybrid functionals, and different basis sets have been applied and compared. Both the stoichiometric and the reduced (111) surfaces are considered, where the electronic structure of the latter is obtained by introducing oxygen vacancies on the topmost or the subsurface oxygen layer. Both the potential energy surfaces of the reduced ceria surface and the adsorbate-surface complex are characterized by numerous local minima, of which the relative stability depends strongly on the electronic structure method of choice. Bent CO2 configurations in close vicinity to the surface oxygen vacancy that partially re-oxidize the reduced ceria surface have been identified as the most probable stable minima. However, the oxygen vacancy concentration on the surface turns out to have a direct impact on the relative stability of possible adsorption configurations. Finally, the vibrational analyses of selected adsorbed species on both the stoichiometric and reduced surfaces show promising agreement with previous theoretical and experimental results.We have investigated the dynamics of liquid water confined in mesostructured porous silica (MCM-41) and periodic mesoporous organosilicas (PMOs) by incoherent quasielastic neutron scattering experiments. The effect of tuning the water/surface interaction from hydrophilic to more hydrophobic on the water mobility, while keeping the pore size in the range 3.5 nm-4.1 nm, was assessed from the comparative study of three PMOs comprising different organic bridging units and the purely siliceous MCM-41 case. An extended dynamical range was achieved by combining time-of-flight (IN5B) and backscattering (IN16B) quasielastic neutron spectrometers providing complementary energy resolutions. Liquid water was studied at regularly spaced temperatures ranging from 300 K to 243 K. In all systems, the molecular dynamics could be described consistently by the combination of two independent motions resulting from fast local motion around the average molecule position and the confined translational jump diffusion of its center of mass. All the molecules performed local relaxations, whereas the translational motion of a fraction of molecules was frozen on the experimental timescale. This study provides a comprehensive microscopic view on the dynamics of liquid water confined in mesopores, with distinct surface chemistries, in terms of non-mobile/mobile fraction, self-diffusion coefficient, residence time, confining radius, local relaxation time, and their temperature dependence. Importantly, it demonstrates that the strength of the water/surface interaction determines the long-time tail of the dynamics, which we attributed to the translational diffusion of interfacial molecules, while the water dynamics in the pore center is barely affected by the interface hydrophilicity.A precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.The onset of shear thinning and the transition from Newtonian to non-Newtonian behavior in the viscous flow of select chalcogenide and oxide network glass-forming liquids in the deeply supercooled regime and its temperature dependence are studied using parallel plate rheometry. GSK805 concentration In all cases, the onset occurs at a shear rate γ̇c that is several orders of magnitude lower than the shear relaxation rate τ0-1 and the former increases with increasing temperature. These results are in good qualitative agreement with the predictions of the existing models of shear relaxation and shear thinning based on the nonlinear Langevin equation theory, random first order transition theory, and the free volume model. However, in contrast to the theoretical predictions, the reduced shear rate W0 (=τ0γ̇c) at the onset is found to range between 10-3 and 10-5 and decrease with increasing temperature. This temperature dependence becomes stronger with increasing fragility of the liquid. These results likely indicate that the shear thinning mechanism in network liquids could be fundamentally different from those in molecular, metallic, or polymeric glass-formers.