TY - GEN A1 - Horenko, Illia A1 - Weiser, Martin T1 - Adaptive Integration of Multidimensional Molecular Dynamics with Quantum Initial Conditions N2 - The paper presents a particle method framework for resolving molecular dynamics. Error estimators for both the temporal and spatial discretization are advocated and facilitate a fully adaptive propagation. For time integration, the implicit trapezoidal rule is employed, where an explicit predictor enables large time steps. The framework is developed and exemplified in the context of the classical Liouville equation, where Gaussian phase-space packets are used as particles. Simplified variants are discussed shortly, which should prove to be easily implementable in common molecular dynamics codes. A concept is illustrated by numerical examples for one-dimensional dynamics in double well potential. T3 - ZIB-Report - 02-29 KW - particle methods KW - adaptivity KW - classical Liouville equation KW - molecular dynamics Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-6967 ER - TY - GEN A1 - Lasser, Caroline A1 - Röblitz, Susanna T1 - Computing expectation values for molecular quantum dynamics N2 - We compute expectation values for the solution of the nuclear Schrödinger equation. The proposed particle method consists of three steps: sampling of the initial Wigner function, classical transport of the sampling points, weighted phase space summation for the final computation of the expectation values. The Egorov theorem guarantees that the algorithm is second order accurate with respect to the semiclassical parameter. We present numerical experiments for a two-dimensional torsional potential with three different sets of initial data and for a six-dimensional Henon-Heiles potential. By construction, the computing times scale linearly with the number of initial sampling points and range between three seconds and one hour. T3 - ZIB-Report - 09-30 KW - time dependent Schrödinger equation KW - molecular quantum dynamics KW - expectation values KW - Wigner functions Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11461 SN - 1438-0064 ER -