Potential Energy Surfaces and Dynamics of High Energy Species
Technical Report,01 Oct 2005,30 Sep 2008
Iowa State University Ames United States
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Several papers on ionic liquids have been published or submitted as a result of this grant. The first set of papers used second order perturbation theory to study the geometries and substituent effects of the cations commonly employed in energetic ionic liquids. These are variously substituted triazolium, tertazolium, and pentazolium cations. The heats of formation of all species were predicted using G2 and G3 theory. It was consistently found that the most energetic substituents are -CN and - N3. When one cation is combined with one anion, proton transfer almost always occurs with no intervening energy barrier, yielding a neutral pair. When two ion pairs are considered, conceptually similar to the face of a crystal, the ion separated species is predicted to be 6 kcalmol lower in energy than the double proton transferred neutral species. These calculations were done using coupled cluster theory, but this level of theory is too expensive to study larger clusters. Therefore, we have turned to the fragment molecular orbital method, which can retain the accuracy of full electronic structure theory calculations, while greatly reducing the cost.
- Inorganic Chemistry