Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 76: Methods in Computational Materials Modelling (methodological aspects, numerics)
MM 76.3: Talk
Friday, March 16, 2018, 11:45–12:00, TC 006
Generalized Langevin Thermostats for Tuning Dynamical Properties in Quantum Dynamics — •Mariana Rossi1, Venkat Kapil2, and Michele Ceriotti2 — 1Fritz Haber Institute of the Max Planck Society, Berlin, Germany — 2EPFL, Switzerland
Generalized Langevin Equation (GLE) thermostats have been used very effectively as a tool to manipulate and optimize the sampling of thermodynamic ensembles and the associated static properties. Here [1] we show that a similar, exquisite level of control can be achieved for the dynamical properties computed from thermostatted trajectories. By developing quantitative measures of the disturbance induced by the GLE to the Hamiltonian dynamics of a harmonic oscillator, we show that these analytical results accurately predict the behavior of strongly anharmonic systems.We address the use of thermostats in the context of approximate path-integral-based models of quantum nuclear dynamics, demonstrating that a custom-tailored GLE can alleviate some of the artifacts associated with these techniques, improving the quality of results for the modelling of vibrational dynamics of molecules, liquids and solids. Finally we show the power of this technique by showing the importance of nuclear quantum effects in the close to full suppression of NH stretch signals in porphyrin derivatives. [1] M. Rossi, V. Kapil, M. Ceriotti, JCP 148, 102301 (2018)