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Molecular dynamics simulations are used for calculating the optical Kerr effect (OKE) spectra of 1-methoxyethylpyridinium dicyanoamide, a room-temperature ionic liquid (IL). The studies have shown that the theoretical methodology has a vital impact on the speed of molecular dynamics simulations of polarizable systems.

The extraordinary stability of the photoinduced red form of a cationic spiropyran is used for obtaining in situ X-ray diffraction evidence of its molecular structure. The density functional theory calculations have shown that the stabilization of the red form of the cationic relative to the neutral spiropyran is thermodynamically controlled, through compensation of the charge within the zwitterion by the methylpyridinium group.

The thermophysical studies of two isomeric room-temperature ionic liquids (RTILs), n-butyl-3-methyl-pyridinium tetrafluoroborate and n-butyl-4-methyl-pyridinium tetrafluoroborate are presented. The results from the studies helped to obtain the coefficients of thermal expansion, molar refractions, and dynamic viscosities and calculate the entropies and enthalpies of surface formation per unit surface area.

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.