I³MS - Kühne Seminar
Prof. Dr. Thomas Kühne - Quantum Mechanics in a Glass of Water
Institut für Physikalische Chemie, Johannes Gutenberg University Mainz
A new energy decomposition analysis for periodic systems based on absolutely localized molecular orbitals is presented [1, 2]. In combination with the recently developed ”Car-Parrinello-like approach to Born-Oppenheimer MD”  this not only allows for ab initio molecular dynamics simulations on previously inaccessible time and length scales, but also provide unprecedented insights into the nature of hydrogen bonding between water molecules. However, in contrast to the original scheme, large integration time steps can be used. By this means the best of the Born-Oppenheimer and the Car-Parrinello methods are unified, which not only extends the scope of either approach, but allows for ab-initio simulations previously thought not feasible. The effectiveness of this new combined approach is demonstrated on liquid water and the water/air interface [4, 5]. Our simulations reveal that although a water molecule forms, on average, two strong donor and two strong acceptor bonds, there is a significant asymmetry in the energy of these contacts. We demonstrate that this asymmetry is a result of small instantaneous distortions of hydrogen bonds and show that the distinct features of the X-ray absorption spectra originate from molecules with high instantaneous asymmetry [1, 2, 6, 7].
 T. D. Kühne and R. Z. Khaliullin, Nature Comm. 4, 1450 (2013).
 R. Z. Khaliullin and T. D. Kühne, Phys. Chem. Chem. Phys. 15, 15746 (2013).
 T. D. Kühne, M. Krack, F. Mohamed and M. Parrinello, Phys. Rev. Lett. 98, 066401 (2007).
 T. D. Kühne, M. Krack and M. Parrinello, J. Chem. Theory Comput. 5, 235 (2009).
 T. D. Kühne, T. A. Pascal, E. Kaxiras and Y. Jung, J. Phys. Chem. Lett. 2, 105 (2011).
 C. Zhang, R. Z. Khaliullin, D. Bovi, L. Guidoni and T. D. Kühne, J. Chem. Phys. Lett. 4, 3245 (2013)
 R. Z. Khaliullin and T. D. K¨uhne, submitted to J. Am. Chem. Soc.