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A study to examine the mixtures of ionic and molecular liquids from structural and thermodynamic perspectives is conducted. Findings reveal that the mixtures of ionic and molecular liquids are generally highly asymmetric and large differences in molecular size, shape and kinds of dominant interaction of their components are observed.

The interactions of nitrous oxide with fluorinated liquids was investigated by reporting original experimental results on gas solubility and interpreting them using molecular simulation. Nitrous oxide was found to be highly soluble in the three fluorinated liquids studied, with mole fraction solubilities on the order of 0.03 under ambient conditions.

Neutron diffraction was used to determine the liquid structure of 1,3-dimethylimidazolium bis{(trifluoromethyl)sulfonyl}amide {[dmim](NT[f.sub.2])}. The liquid structure of 1,3-dimethylimidazolium bis{(trifluoromethyl)sulfonyl}amide shows a decreasing affinity for hydrogen bonding with the cation as a function of both charge density and anion size.

A set of force field parameters is proposed for the molecular simulation of ionic liquids containing the anions trifluoromethylsulfate and bis(trifluoromethylsulfonyl)imide, also known as triflate and bistriflylimide, respectively. The force-field models are validated against crystal structures and liquid-state densities.

Construction of a new force field for the molecular modeling of ionic liquids of the dialkylimidazolium family based on the OPLS-AA amber framework is presented. The new model is reportedly validated by comparison of simulated data with experimental data that exist on fourteen different salts.

Raman spectroscopy, molecular dynamics (MD) and ab initio studies are used for studying the conformational landscape of the bis(fluorosulfonyl)amide ([[FSI].sup.-]) anion. The conformational behavior of the ion [[FSI].sup.-] is discussed in terms of the solvation properties of the corresponding ionic liquids.

A new scaling concept is used for determining the relationship between the viscosity coefficients and volumetric properties of the molecular and ionic liquids. The scaling factor is shown to be highly dependent on the number of covalent bonds.

The studies of parametrization of a force field for the molecular simulation of common ionic liquids within the framework of statistical mechanics are described. The ion models used are cations of the 1,2,3-trialkylimidazolium and alkoxycarbonyl imidazolium families and alkylsulfate and alkylsulfonate anions.

The conformational behavior of two types of commonly used ionic liquid ions, the anion bis(trifluoromethanesulfonyl)-amide (Nt[f.sub.2] and the cations N-propyl- and N-butyl-N-methylpyrrolidinium are discussed. The results from the studies provide insight into the solvation properties of the corresponding ionic liquids.

The calculations of equilibrium thermodynamic and structural properties concerning the cations alkylimidazolium, tetra-alkylphosphonium, and N-alkylpyridinium, and anions chloride, bromide, and dicyanamide is reported. The results show that the rotation of the methyl group around the NAP-C1 bond in N-methylimidazolium is almost free, whereas the C1-C2 bond in longer alkyl chains adopts an orientation perpendicular to the aromatic ring.

A structural analysis is performed on the solvation of nonpolar, polar and associating solutes in imidazolium-based ionic liquids. The analysis has confirmed that the solvation of nonpolar, polar or associating solutes in the ionic liquids can be very diverse, given the presence of the segregated domains.

The nanometer-scale structuring in room-temperature ionic liquids of family 1-alkyl-3-methylimidazolium is observed using molecular simulation. The consequences of these nonstructural features on the properties of the ionic liquids are analyzed.

The structural details of the liquid fluorocarbon and hydrocarbon phases and the role of electrostatics in the interactions of CO2 with those liquids are presented. This analysis permits the molecular interpretation of the experimental fact that the fluorocarbon solvents always dissolve larger amounts of a particular gas than the equivalent hydrogencarbons, but fails to explain the differences between the solubility of oxygen and carbon dioxide in a fluorinated liquid.

Torsional potential energy profiles for two classes of substituted perfluoroalkanes-hydrocarbon-fluorocarbon diblocks and 1-bromoperfluorolakes-are calculated ab initio by incorporating correlation effects and using flexible basis sets. Dihedral angle functions for use in molecular simulations are derived from the quantum mechanical profiles.

A high-precision apparatus based on an extraction method is used to measure the solubility of hexafluoroethane in water in the temperature range of 287-328 K at pressures close to atmospheric. The experimental data are used to calculate Henry's law coefficients H(sub 2,1)(p1(super sat, T), whose temperature dependence is represented by appropriate correlations.

Deep eutectic solvents (DESs) are mixtures of ionic compounds and molecular hydrogen bond donors. Due to the many components and their different interacting subgroups, they give rise to a plethora of many different interactions which can be studied by ab initio molecular dynamics simulations, because within this method all the forces are calculated on the fly and no parametrization prior to the calculation is necessary. Since DESs can be applied in gas capture, for example for SO 2 absorption, we performed ab initio molecular dynamics studies of both the pure choline chloride/glycerol DES and the same mixed with SO 2 . We identified the hydrogen bonding and other specific interactions between all components. With addition of SO 2 , we observed a decrease in the anion-OH group interplay, because the chloride anions form complexes with the SO 2 molecules. Furthermore, the SO 2 molecules are incorporated into the hydrophobic network and the interaction between the hydrogen bonds of all OH groups remain constant. This decrease of anion-OH interaction might be responsible for the more fluid state of the SO 2 -DESs mixture than the pure DES. [ABSTRACT FROM AUTHOR]