A subtle difference: In ionic liquids the "weak" dispersion forces have a significant impact on shape of potential energy surface, which results in shallow profile when all contributions are considered. Such findings commonly accepted to determine liquid state. Supporting information for this article is available WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z705526_s.pdf or from author. Please note: The publisher not responsible content functionality any supporting supplied by...

The structure of the hydrated electron, which is a key species in radiative processes water, has remained elusive. traditional cavity model been questioned recently, but newly suggested picture an electron delocalized over region enhanced water density controversial. Here, we present results from ab initio molecular dynamics simulations, where not only excess also valence electrons surrounding molecules are described quantum mechanically. Unlike previous one-electron pseudopotential...

Understanding the properties of hydrated electrons, which were first observed using pulse radiolysis water in 1962, is crucial because they are key species many radiation chemistry processes. Although time-resolved spectroscopic studies and molecular simulations have shown that an electron (prepared, for example, by photoionization) relaxes quickly to a localized, cavity-like structure ∼2.5 Å radius, this picture has recently been questioned. In another experimental approach, negatively...

The optical spectrum of the hydrated (aqueous) electron, e(aq)(–), is primary observable by means which this species detected, monitored, and studied. In theoretical calculations, has most often been simulated using one-electron models. Here, we present ab initio simulations that in both bulk water and, for first time, at water/vapor interface, density functional theory its time-dependent variant. Our results indicate approach provides a reliable description, quantitative agreement with...

The process of electron localization on a cluster 32 water molecules at 20, 50, and 300 K is unraveled using ab initio molecular dynamics simulations. In warm, liquid clusters, the excess relaxes from an initial diffuse weakly bound structure to equilibrated, strongly species within 1.5 ps. contrast, in cold, glassy clusters relaxation processes not completed becomes trapped metastable surface state with intermediate binding energy. These results question validity extrapolations properties...

The existence of like-charge guanidinium–guanidinium contact ion pairs in water is established by ab initio molecular dynamics simulations. Despite direct electrostatic repulsion, a pair observed between two guanidinium cations, stabilized primarily their amphiphilic behavior and van der Waals interactions. In control simulation performed for aqueous ammonium no such formed. This the strongest computational evidence so far specific pairing cations water, with important implications...

Microorganisms accumulate molar concentrations of compatible solutes like ectoine to prevent proteins from denaturation. Direct structural or spectroscopic information on the mechanism and about hydration shell around are scarce. We combined surface plasmon resonance (SPR), confocal Raman spectroscopy, molecular dynamics simulations, density functional theory (DFT) calculations study local its influence binding a gene-5-protein (G5P) single-stranded DNA (dT25). Due very high hygroscopicity...

Ectoine is an important osmolyte, which allows microorganisms to survive in extreme environmental salinity. The hygroscopic effects of ectoine pure water can be explained by a strong binding behavior whereas study on the salty solution yet missing. We provide Raman spectroscopic evidence that influence and NaCl are opposing completely independent each other. effect formation strongly hydrogen-bonded molecules around compensate salt dynamics. mechanism corroborated first principles...

The hydrated electron is a crucial species in radiative processes, and it has been speculated that its behavior at the water surface could lead to specific interfacial chemical properties. Here, we address fundamental questions concerning structure energetics of an water. We use method ab initio molecular dynamics, which was shown provide faithful description solvated electrons large clusters bulk present results clearly demonstrate mostly buried layer, with only about 10 % density...

The first hybrid crown ether with two adjacent disilane fragments was synthesized through reaction of O(Si2Me4Cl)2 (3) O(C2H4OH)2. By means DFT calculations, the complexation ability 1,2,4,5-tetrasila[12]crown-4 (7) towards Li+ determined to be considerably higher compared [12]crown-4.

We present an ab initio parametrization scheme for explicitly dipole-polarizable force fields the simulation of molecular liquids. The allows for, in principle, arbitrarily coarse-grained representations. All parameters field are derived from first-principles, based on simple physical arguments. Only one fit parameter enters parametrization, a global scaling factor size particles, which is adjusted to reproduce experimental mass density. As important examples and first time, polarizable...

Ionization in the condensed phase and molecular clusters leads to a complicated chain of processes with coupled electron-nuclear dynamics. It is difficult describe such dynamics conventional nonadiabatic schemes since number states swiftly increases as system grows. therefore attractive use direct electron nuclear propagation real-time time-dependent density functional theory (RT-TDDFT). Here we report RT-TDDFT benchmark study on simulations singly doubly ionized water monomer dimer...

The quantum theory of atoms in molecules gives access to well-defined local atomic energies. Due their locality, these energies are potentially interesting fitting atomistic machine learning models as they inform about physically relevant properties. However, computationally, quantum-mechanically accurate notoriously difficult obtain for large systems. Here, we show that by employing semiempirical correlations between different components the total energy, can at a moderate cost. We employ...

Ab initio molecular dynamics simulations were performed with the aim to follow two scenarios for an excess electron in cold water clusters. In first one, is attached a quenched neutral cluster. Such electron, initially very delocalized and loosely bound, shrinks somewhat increases its vertical detachment energy 1−1.5 eV within several picoseconds. Unlike warm liquid clusters, this system does not, however, reach more compact strongly bound structure. contrast, if equilibrated negatively...

Core-level spectra of liquids can be difficult to interpret due the presence a range local environments. We present computational methods for investigating core-level based on idea that both structural parameters and X-ray behave as functions atomic configuration around absorbing site. identify correlations between spectral intensities in defined regions interest, using oxygen K-edge excitation spectrum liquid water test case. Our results show this kind analysis find main structure-spectral...

We present a coarse-grained polarizable molecular dynamics force field for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]). For treatment of electronic polarizability, we employ Drude model. Our results show that new explicitly reproduces important static and dynamic properties such as mass density, enthalpy vaporization, diffusion coefficients, or electrical conductivity in relevant temperature range. In situations where an explicit polarizability might be...

The series of oligogermanes Pri3Ge(GePh2)nGePri3 (n = 0, 2; n 1, 3; 2, 4; 3, 5) were prepared by the hydrogermolysis reaction. All four species characterized NMR (1H and 13C) UV/visible spectroscopy as well cyclic voltammetry differential pulse voltammetry. exhibited a successive red shift in their absorbance maxima length Ge–Ge chain was increased, these molecules also became easier to oxidize increased. X-ray crystal structures 4 5 trigermane HPh2GeGePh2GePh2H (6) determined. pentagermane...

The impact of microhydration on the electronic structure and reactivity H3O moiety is investigated by ab initio calculations. In gas phase, a radical with spin density localized its hydrogen end, which only kinetically stable readily decomposes into water molecule atom. When solvated single molecule, preserves to large extent character, however, two molecules are already capable shift most solvent. With three solvating this practically completed system best described as solvent-separated...