Dresden 2014 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 77: Focus Session: Frontiers of Electronic Structure Theory - Non-Equilibrium Phenomena at the Nano-Scale V (organized by O)
TT 77.10: Talk
Wednesday, April 2, 2014, 18:45–19:00, TRE Ma
Efficient Path-Integral Molecular Dynamics with High-Order Decomposition of the Boltzmann Operator — •Igor Poltavsky1, Kim Kwang2, and Alexandre Tkatchenko1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — 2Center for Superfunctional Materials, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea
Recently it has become possible to reach the so-called "chemical accuracy" of 1 kcal/mol for the binding energies of small molecules and supramolecular systems, which is an essential prerequisite for predictive first-principles modeling. However, at this level of accuracy another serious issue arises, namely the need to accurately account for the quantum nature of (light) nuclei that plays a vital role in the structure, stability, and dynamical properties of many systems, including water, ice, as well as most biological molecules.
The most widely used tool to study quantum nuclear effects is the imaginary-time path integral (PI) approach which can be easily incorporated into ab initio calculations. Here we propose efficient PI molecular dynamics (MD) methods based on third and fourth order decompositions of the Boltzmann operator. These methods decrease the required number of replicas by more than a factor of two comparing to the standard second-order PIMD simulations, while at the same time visibly increasing the accuracy for a wide range of temperatures. Results are shown for model systems and an accurate quantum-mechanical model of the water molecule.