Sulfur dioxide in water: structure and dynamics studied by an ab initio quantum mechanical charge field molecular dynamics simulation.

An ab initio Quantum Mechanical Charge Field Molecular Dynamics Simulation (QMCF MD) was performed to investigate structure and dynamics behavior of hydrated sulfur dioxide (SO(2)) at the Hartree-Fock level of theory employing Dunning DZP basis sets for solute and solvent molecules. The intramolecular structural characteristics of SO(2), such as S═O bond lengths and O═S═O bond angle, are in good agreement with the data available from a number of different experiments. The structural features of the hydrated SO(2) were primarily evaluated in the form of S-O(wat) and O(SO(2))-H(wat) radial distribution functions (RDFs) which gave mean distances of 2.

Hydrolysis of tetravalent group IV metal ions: an ab initio simulation study.

Simulations of the tetravalent group IV metal ions, Ge(IV), Sn(IV), and Pb(IV), in aqueous solution were performed using ab initio quantum mechanical charge field molecular dynamics (QMCF MD). The process of hydrolysis, which occurred for each of the metal ions, was analyzed in terms of the time evolution of solvent configuration. Several important factors involved in the initiation of proton dissociation from first shell water molecules are discussed in connection to the nature of proton mobility in aqueous solution.

Structural and dynamic aspects of hydration of HAsO4(-2): an ab initio QMCF MD simulation.

An ab initio quantum mechanical charge field simulation has been carried out in order to obtain molecular level insight into the hydration behavior of HAsO4(-2), one of the major biologically active components of As(V) oxoanion in neutral to slightly alkaline aqueous medium. Moreover, a geometrical definition of hydrogen bonding has been used to probe and characterize both solute-solvent and solvent-solvent hydrogen bonding present in the system. The asymmetry of the anion induced by the protonation of one of the oxygens of the arsenate anion causes rather irregular hydration structure.

Structural and dynamical aspects of the unsymmetric hydration of Sb(III): an ab initio quantum mechanical charge field molecular dynamics simulation.

An ab initio quantum mechanical charge field molecular dynamics (QMCF MD) simulation was performed to investigate the behavior of the Sb(3+) ion in aqueous solution. The simulation reveals a significant influence of the residual valence shell electron density on the solvation structure and dynamics of Sb(3+). A strong hemidirectional behavior of the ligand binding pattern is observed for the first hydration shell extending up to the second hydration layer.

Temperature dependence of structure and dynamics of the hydrated Ca2+ ion according to ab initio quantum mechanical charge field and classical molecular dynamics.

Simulations using ab initio quantum mechanical charge field molecular dynamics (QMCF MD) and classical molecular dynamics using two-body and three-body potentials were performed to investigate the hydration of the Ca(2+) ion at different temperatures. Results from the simulations demonstrate significant effects of temperature on solution dynamics and the corresponding composition and structure of hydrated Ca(2+). Substantial increase in ligand exchange events was observed in going from 273.

Revisiting the hydration of Pb(II): a QMCF MD approach.

A quantum mechanical charge field (QMCF) molecular dynamics (MD) study of Pb(II) in an aqueous medium was carried out in order to gain insight into its solvation behavior, for both structural and dynamic aspects. Applying the advanced methodology and different basis sets, some new aspects concerning the solvation of Pb(II) have been revealed. One of the most interesting outcomes of the current simulation is the variation of first shell coordination number from 7 to 9 in the Pb(H2O)n(2+) complex with Pb(H2O)8(2+) as a major species.

Beryllium(II): the strongest structure-forming ion in water? A QMCF MD simulation study.

A quantum mechanical charge field (QMCF) molecular dynamics (MD) simulation including the first and second hydration shells in the QM region has been carried out to describe the structural and dynamical properties of Be(2+) in aqueous solution. In this methodology, the full first and second hydration shells are treated by ab initio quantum mechanics supplemented by a fluctuating electrostatic embedding technique. From the simulation, structural properties were extracted and were found to be in good agreement with previously published experimental and theoretical results.

Hydrated germanium (II): irregular structural and dynamical properties revealed by a quantum mechanical charge field molecular dynamics study.

Structural and dynamical properties of Ge (II) in aqueous solution have been investigated using the novel ab initio quantum mechanical charge field (QMCF) molecular dynamics (MD) formalism. The first and second hydration shells were treated by ab initio quantum mechanics at restricted Hartree-Fock (RHF) level using the cc-pVDZ-PP basis set for Ge (II) and Dunning double-zeta plus polarization basis sets for O and H. Besides ligand exchange processes and mean ligand residence times to observe dynamics, tilt- and theta-angle distributions along with an advanced structural parameter, namely radial and angular distribution functions (RAD) for different regions were also evaluated.

The hydration structure of Sn(II): an ab initio quantum mechanical charge field molecular dynamics study.

The structural properties of the hydrated Sn(2+) ion have been investigated using ab initio quantum mechanical charge field molecular dynamics (QMCF MD) simulations at double-xi HF quantum mechanical level. The results from the work significantly extend previous study using QM/MM MD simulation and are in good agreement with X-Ray and EXAFS diffraction experiments. The data indicate a set of characteristics for the first hydration shell uncommon among metal ions.