The temperature dependence of the adsorption of NO on Pt{211}: A RAIRS and DFT investigation

RAIRS experiments have been performed to investigate the adsorption of NO on Pt{211}. Results show that adsorption is complex and strongly temperature dependent. At 307 K, three bands are seen at saturation with frequencies of 1801, 1609, and 1576 cm(-1). However, at 120 K only two bands, at 1688 and 1620 cm(-1), are observed. To help with the assignment of these vibrational bands, DFT calculations were also performed. The calculations show that a bridged NO species, bonded to the step edge, is the most stable species on the surface and gives rise to the band observed at 1610-1620 cm(-1). The calculations also suggest that the temperature dependence of NO adsorption on Ptf{211} can be assigned to NO dissociation which occurs at room temperature but not at 120 K. In particular, the RAIRS band observed at 1801 cm(-1), which is observed on adsorption at 307 K but not at 120 K, is tentatively assigned to the formation of an O-NO complex. This species forms when a NO molecule bonds on top of an O atom, which results from the dissociation of NO on the Pt{211} surface at room temperature.

Temperature dependence of the electrical conductivity of imidazolium ionic liquids

The electrical conductivities of 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids and of 1-hexyl-3-methylimidazolium ionic liquids with different anions were determined in the temperature range between 123 and 393 K on the basis of dielectric measurements in the frequency range from 1 to 10(7) Hz. Most of the ionic liquids form a glass and the conductivity values obey the Vogel-Fulcher-Tammann equation. The glass transition temperatures are increasing with increasing length of the alkyl chain. The fragility is weakly dependent on the alkyl chain length but is highly sensitive to the structure of the anion. (c) 2008 American Institute of Physics.

Temperature Dependence of the Primary Relaxation in 1-Hexyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide

We present results from complementary characterizations of the primary relaxation rate of a room temperature ionic liquid (RTIL), 1-hexyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl} imide, [C(6)mim][Tf2N], over a wide temperature range. This extensive data set is successfully merged with existing literature data for conductivity, viscosity, and NMR diffusion coefficients thus providing, for the case of RTILs, a unique description of the primary process relaxation map over more than 12 decades in relaxation rate and between 185 and 430 K. This unique data set allows a detailed characterization of the VTF parameters for the primary process, that are: B = 890 K, T-0 = 155.2 K, leading to a fragility index m = 71, corresponding to an intermediate fragility. For the first time neutron spin echo data from a fully deuteriated sample of RTIL at the two main interference peaks, Q = 0.76 and 1.4 angstrom(-1) are presented. At high temperature (T > 250 K), the collective structural relaxation rate follows the viscosity behavior; however at lower temperatures it deviates from the viscosity behavior, indicating the existence of a faster process.

Enlargement and the European Union’s Absorption Capacity: ‘oft-forgotten’ condition or additional obstacle to membership?

The Austrian government may have failed in its efforts in 2005 to have ‘privileged partnership' inserted into the European Union's framework for accession negotiations with Turkey, but this did not prevent the country's Chancellor, Wolfgang Schussel, from claiming that ‘for the first time ever, we have set an extra condition which will yet be very important in the future for Europe, namely the ability of the Union to take in new members'. Indeed, since its inclusion in the framework for negotiations, the EU's ‘capacity to absorb' new members is referred to as a new criterion for further enlargement of the European Union (EU). When opponents of Turkey 's membership, like Schussel, celebrate the emphasis on the EU's ‘absorption capacity', Turks generally regard it as specially-designed extra obstacle to their membership aspirations even if the EU's ‘absorption capacity' is a permanent agenda item whenever the EU discusses enlargement. This article explores the origins of this – supposedly new – condition and argues that the increased emphasis on the EU's ‘absorption capacity' can be explained by the shifts in the dynamics of EU enlargement.