alexa On the dynamics of ionic liquids: comparisons between electronically polarizable and nonpolarizable models II.
Bioinformatics & Systems Biology

Bioinformatics & Systems Biology

Journal of Data Mining in Genomics & Proteomics

Author(s): Yan T, Wang Y, Knox C, Yan T, Wang Y, Knox C, Yan T, Wang Y, Knox C

Abstract Share this page

Abstract An electronically polarizable model has been developed for the ionic liquid (IL) 1-ethyl-3-methyl-imidazolium nitrate (EMIM(+)/NO(3)(-)) (Yan et al. J. Phys. Chem. B DOI:10.1021/jp9089112). Molecular dynamics simulations were then performed with both the polarizable and nonpolarizable models. Both models exhibited certain properties that are similar to a supercooled liquid behavior even though the simulations were run at 400 K (89 K above the melting point of EMIM(+)/NO(3)(-)). The ionic mean-squared displacement and transverse current correlation function of both models were well represented by a memory function with a fast Gaussian initial relaxation followed by the two-step exponential functions for beta- and alpha- structural relaxations. Another feature shared by both models is the dynamic heterogeneity, which highlights the complex dynamic behavior of ILs. Apart from the overall slow dynamics, the relaxation of the H-atoms attached to the methyl group demonstrates a "free rotor" type of motion. Also, the ethyl group shows the fastest overall relaxation, due to the weak electrostatic interactions on it. Such flexibility enhances the entropic effect and thus favors the liquid state at room temperature. For the dynamical properties reported in this paper, the polarizable model consistently exhibited faster relaxations (including translational and reorientational motions), higher self-diffusion and ionic conductivity, and lower shear viscosity than the nonpolarizable model. The faster relaxations of the polarizable model result from attenuated long-range electrostatic interactions caused by enhanced screening from the polarization effect. Therefore, simulations based on the polarizable model may be analogous to simulations with the nonpolarizable model at higher temperatures. On the other hand, the enhanced intermolecular interactions for the polarizable model at short-range due to the additional charge-dipole and dipole-dipole interactions result in a red shift of the intramolecular C-H stretch spectrum and a higher degree of ion association, leading to a spectrum with enhanced conductivity across the whole frequency range. The vibrational motion associated with the intermolecular hydrogen bonding is highly IR active, highlighting the importance of hydrogen bond dynamics in ILs. This article was published in J Phys Chem B and referenced in Journal of Data Mining in Genomics & Proteomics

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

  • 3rd World Congress on Human Genetics
    August 14-15, 2017 Edinburgh, Scotland
  • 9th International Conference on Bioinformatics
    October 23-24, 2017 Paris, France
  • 9th International Conference and Expo on Proteomics
    October 23-25, 2017 Paris, France

Relevant Topics

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version