Modeling O(3P) and Ar scattering from the ionic liquid [emim] [NO3] at 5 eV with hybrid QM/MM molecular dynamics

Scott Yockel, George C Schatz

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

In this paper, we develop a hybrid QM/MM-MD direct dynamics method for the study of Ar and O scattering from room-temperature ionic liquids (RTIL) at hyperthermal energies, with the goal of providing an understanding of the reactivity of ionic liquids as potential hypergolic fuels. The RTIL is chosen to be 1 -ethyl3-methylimidazolium nitrate ([emim][N03]) as the bulk properties of this have been analyzed experimentally and theoretically, and a force field has been developed. Within our simulation time of 7.3 ps, Ar collisions with the liquid surface cause 2-3 proton transfers to occur from the imidazolium ring to the anion, and a small fraction of these events leads to the desorption of neutral "emim" or HNO3 species. These chargetransfer processes also occur for O(3P) collisions, but in addition, there is a rich amount of chemical change at the surface leading to four main collision types, reaction with NO3 to form species like [NO2] and O2, O addition to the imidazolium ring causing ring scission, H abstractions from the hydrocarbon chains (ethyl or methyl) or imidazolium ring generating OH, and O atom inelastic scattering. Within the MSINDO model, the major scattered products (all are neutral) from the O collisions, with their probabilities in parentheses, are O (0.13), emim (0.12), HNO2 (0.05), HNO3 (0.04), and OH (0.04). Of these products, only OH is unique to O atom collisions; the HNO2 and HNO3 products also arise when the incident atom is Ar or O.

Original languageEnglish
Pages (from-to)14241-14248
Number of pages8
JournalJournal of Physical Chemistry B
Volume114
Issue number45
DOIs
Publication statusPublished - Dec 8 2010

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Ionic Liquids
Ionic liquids
Nitrates
Molecular dynamics
nitrates
Scattering
molecular dynamics
Atoms
collisions
liquids
scattering
rings
Inelastic scattering
Proton transfer
Hydrocarbons
products
Anions
Desorption
atoms
Negative ions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Modeling O(3P) and Ar scattering from the ionic liquid [emim] [NO3] at 5 eV with hybrid QM/MM molecular dynamics. / Yockel, Scott; Schatz, George C.

In: Journal of Physical Chemistry B, Vol. 114, No. 45, 08.12.2010, p. 14241-14248.

Research output: Contribution to journalArticle

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