(4eo) A Tale of Two Studies: Dynamics and Timing

Multi-scale material simulations comprise the bridge between the microscopic length and time scale, and the macroscopic world. The first part will show how real-time trajectory calculations have provided for the first time a detailed dynamical picture of organic reactions involving cycloadditions [1-5]. For example, in 1,3-dipolar cycloadditions, the previously reported linear correlation between activation barriers and the energy required to distort the reactants to their transition-state geometries is now understandable in terms of the requirement for vibrational excitation [2,3]. In the case of carbene cycloadditions, we explored the range of geometries sampled in productive trajectories, as well as the timing of bond formation [4].

    The second part will focus on large material simulations such as TiO₂ surface and polyurea/polyimide aerogels. An analytic potential energy function for dimethyl methylphosphonate (DMMP) interacting with TiO₂surface were developed, based on accurate cluster models[6]. Another project focuses on the assembly of polyurea aerogels.[7] Atomistic simulations and micropores analysis helped determining the internal structure of polyimide nanoparticles[8].

[1] D. H. Ess, S. E. Wheeler, R. G. Iafe, L. Xu, N. Celebi-Olcum and K. N. Houk, Angew. Chem. Int. Ed. 2008, 47,

      7592

[2] L. Xu, C. E. Doubleday, K. N. Houk, Angew. Chem. Int. Ed.  2009, 48, 2746 (highlighted by Nature Chemistry)

[3] L.  Xu, C. E. Doubleday, K. N. Houk, J. Am. Chem. Soc. 2010, 132, 3029.

[4] L. Xu, C. E. Doubleday, K. N. Houk, J. Am. Chem. Soc. 2011, 133, 17848.

[5] K. Black, P. Liu, L. Xu, C. E. Doubleday, K. N. Houk,  Proc. Natl. Acad. Sci, 2012, 109, 12860 (featured in

      Computational Chemistry Highlights, ScienceDaily) 

[6] L. Xu, L. Yang, W. A. DeJong, W. L. Hase, N. Govind, L. Hans, D. Tunega, J. Phys. Chem. C. under revision

[7] L. Xu, C. Sotiriou-Leventis, and N. Leventis, manuscript in preparation

[8] C. Chidambareswarapattar, L. Xu, C. Sotiriou-Leventis, and N. Leventis, manuscript in preparation