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Center for Nonlinear Studies |
We have developed and implemented a multiscale QM/MM Molecular Dynamics simulation technique comprised of an effective coupling of a fast, real-space grid-based DFT code (GPAW) to classical solvent methods[1]. Due to the grid-based nature of GPAW, the explicit electrostatic coupling of the external MM system via the external potential only ads little extra computational cost, compared to the DFT calculation, without the need for further approximations. We have used this method to perform Born-Oppenheimer MD dynamics, sampling over 100s of picoseconds in parallel trajectories, to study thermally averaged electron transfer pathways in a photocatalyst model system[3], and have shown how the solvent can effectively stabilize coherent excited state modes of a di-iridium complex[2], insights which which proved valuable in the interpretation of free-electron x-ray laser experiments[4]. We are currently working on a polarizable embedding model that will increase accuracy and generality of our coupling.
[1]: Dohn, A. O. & Jónsson, E. Ö; Levi, G.; Mortensen, J. J.; Lopez-Acevedo, O.; Thygesen, K. S.; Jacobsen, K. W.; Ulstrup, J.; Henriksen, N. E.; Møller, K. B.; Jónsson, H., A GPAW Implementation of QM/MM Electrostatic Embedding and Application to a Solvated Diplatinum Complex. J. Chem. Theory Comput., accepted, 2017
[2]: Dohn, A. O.; Jónsson, E. Ö.; Kjær, K. S.; B. van Driel, T.; Nielsen, M. M.; Jacobsen, K. W.; Henriksen, N. E.; Møller, K. B., Direct Dynamics Studies of a Binuclear Metal Complex in Solution: The Interplay Between Vibrational Relaxation, Coherence, and Solvent Effects., J. Phys. Chem. Lett. 2014, 5, 2414–2418
[3]: Dohn, A. O.; Kjær, K. S.; Harlang, T. B.; Canton, S. E.; Nielsen, M. M.; Møller, K. B., Electron Transfer and Solvent-Mediated Electronic Localization in Molecular Photocatalysis. Inorg. Chem. 2016, 55, 10637–10644
[4]: van Driel, T. B.; Kjær, K. S.; Hartsock, R. W.; Dohn, A. O.; Harlang, T.; Cholet, M.; Christensen, M.; Gawelda, W.; Henriksen, N. E.; Kim, J. G.; Haldrup, K.; Kim, K. H.; Ihee, H.; Kim, J.; Lemke, H.; Sun, Z.; Sundström, V.; Zhang, W.; Zhu, D.; Møller, K. B.; Nielsen, M. M.; Gaffney, K. J. Atomistic characterization of the active-site solvation dynamics of a model photocatalyst. Nat. Commun. 2016, 7, 13678
Host: Hannes Jonsson