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Thermal properties, ionic conductivity and self-diffusion coefficients of lithium [Li] salt solutions in a room-temperature ionic liquid (RTIL), bis(trifluoromethanesulfonyl)imide anion [BMMI][TFSI] are determined. The studies indicate the formation of aggregates in which the Li ion coordination with oxygen atom of TFSI anions changes with the Li ion concentration, resulting in a change in the RTIL structure and a reduction of the diffusion coefficient for all the species.

Molecular dynamics (MD) simulation has been used in a detailed investigation of structure and dynamics of molten sodium chlorate, NaClO[sub 3]. Results obtained with nonpolarizable and polarizable models are compared, the latter being implemented by using a fluctuating charges approach for the anions. The partial charges of the nonpolarizable model and the parameters of the polarizable model were obtained by ab initio calculations of a single ClO[sub 3][sup -] anion. The calculated static structure factor of molten NaClO[sub 3] is in good agreement with recent neutron scattering results. A detailed picture of the distribution of cations-around the anions is provided. Proper to the rather large dipole moment of the ClO[sub 3][sup -] anion, short-range dipole ordering between pair of anions is discernible in the MD simulations. The equilibrium structure of molten NaClO[sub 3] is not too affected by including polarization effects on the anions, but significant polarization effects are observed in the dynamics of the simulated system. The ionic diffusion coefficients increase by including polarization effects, so that the polarizable model gives higher conductivity and lower viscosity than the nonpolarizable model. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A combination of Raman spectroscopy and molecular dynamics simulations is employed to study the effect of sulfur dioxide on the structure and dynamics of an ionic liquid. The addition of sulfur dioxide is shown to lead to strong correlation of the ionic motion and interactions in the liquid.

Molecular dynamics (MD) simulations are used for examining the thermodynamics, structure and dynamics of an ionic liquid based on a quaternary ammonium salt with ether side chain, namely N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide, (MOEN[M.sub.2]E TFSI). Walden plot conductivity and viscosity has shown that simulated MOEN[M.sub.2]E TFSI is classified as a poor ionic liquid.

The interaction between minor amounts of S[O.sub.2] and crystalline 1-butyl-3-methyl-imidazolium bromide (BMIBr) which causes immediate melting of the ionic liquid as well as dramatic decrease in its viscosity is described.

Abstract: Hydrogen bonding between pyridazine (PRD) and formamide (FA) molecules has been investigated both experimentally by Raman spectroscopy on their binary mixtures and theoretically by DFT calculations on various gas-phase PRD:FA clusters. The band at 1160cm−1 of PRD was used for the first time as a marker for monitoring the degree of complexation. Upon dilution with FA, a new band at 1169cm−1 is observed and attributed to hydrogen-bonded PRD. The Raman experiments were complemented by DFT calculations and the corresponding structures, vibrational spectra and binding energies were determined. The most stable species were found to be the 1:2 PRD:FA complexes and such stoichiometry is in excellent agreement with the experimental determination. The shift to higher frequency observed to the prominent modes of PRD may be related to a shortening of the NC and CC bonds, upon complexation, which causes a decrease in the electron delocalization in PRD ring. [Copyright &y& Elsevier]