Both first-principles molecular dynamics and theoretical X-ray absorption spectroscopy have been used to investigate the aqueous solvation of cations in 0.5 M MgCl(2), CaCl(2), and NaCl solutions. We focus here on the species-specific effects that Mg(2+), Ca(2+), and Na(+) have on the X-ray absorption spectrum of the respective solutions. For the divalent cations, we find that the hydrogen-bond...

The correspondence between the exact embedding potential and the pair of the electron densities--that of the embedded molecule and that of its environment [Wesolowski and Warshel, J. Phys. Chem. 1993, 97, 8050]--is used to generate the average embedding potential and to subsequently calculate the solvatochromic shifts in a number of organic chromophores in solvents of various polarities. The av...

Using molecular dynamics simulations, small-angle neutron scattering, and a variety of spectroscopic techniques, we evaluated the ion solvation and transport behaviors in aqueous electrolytes containing bis(trifluoromethanesulfonyl)imide. We discovered that, at high salt concentrations (from 10 to 21 mol/kg), a disproportion of cation solvation occurs, leading to a liquid structure of heterogen...

Building on the SVPE (surface and volume polarization for electrostatics) model for electrostatic contributions to the free energy of solvation with explicit consideration of both surface and volume polarization effects, on the SMx approach to including first-solvation-shell contributions, and on the linear relationship between the electric field and short-range electrostatic contributions foun...

Time-dependent Stokes shifts (TDSS) were measured for diverse polarity probes in water, heavy water, methanol, and benzonitrile, by broadband fluorescence up-conversion with 85 fs time resolution. In water the spectral dynamics is solute-independent and quantitatively described by simple dielectric continuum theory of solvation. In methanol the slower part of the TDSS is solute-dependent. A cor...

Room temperature ionic liquids (RTILs) have attracted tremendous interest in recent years as promising media, which could be an alternative to the environmentpolluting, volatile common organic solvents. In this article, we focus on the studies of dynamic Stokes shift of the fluorescence spectra of dipolar solutes in RTILs. These studies throw light on the nature of solvation dynamics in media t...

The Poisson-Boltzmann implicit solvent (PB) is widely used to estimate the solvation free energies of biomolecules in molecular simulations. An optimized set of atomic radii (PB radii) is an important parameter for PB calculations, which determines the distribution of dielectric constants around the solute. We here present new PB radii for the AMBER protein force field to accurately reproduce t...

The analogue of the hydrophobic hydration is explored for Lennard-Jones solutions. The free energy of solvation and its temperature derivatives, both in the constant-pressure process and in the constant-volume process, are obtained numerically for a variety of the size and energy parameters for the solute-solvent Lennard-Jones potential. We identify in the parameter space a region in which the ...

Stabilities and quantum molecular descriptors of cyclophoshphamide (an anticancer drug)-functionalized (8,0) zigzag and (4,4) armchair carbon nanotubes (CNTs) complexes in water were studied using density functional theory (DFT) calculations. Two attachments namely the sidewall- and tip-attachments are considered for the model constructions. Calculations of the total electronic energy (Et) and ...

The first-principles simulation of the electronic structure organic semiconductors in solution poses a number challenges that are not trivial to address simultaneously. In this work, we investigate effects and mutual interplay solvation, alkylization, doping on structural, electronic, optical properties sexithiophene, representative semiconductor molecule. To end, employ (time-dependent) densit...