Combination of the pair density approximation and the Takahashi–Imada approximation for path integral Monte Carlo simulations

Journal Article · Sun Nov 15 04:00:00 EST 2015 · Journal of Computational Physics

DOI:https://doi.org/10.1016/J.JCP.2015.08.020· OSTI ID:22570195

We construct an accurate imaginary time propagator for path integral Monte Carlo simulations for heterogeneous systems consisting of a mixture of atoms and molecules. We combine the pair density approximation, which is highly accurate but feasible only for the isotropic interactions between atoms, with the Takahashi–Imada approximation for general interactions. We present finite temperature simulations results for energy and structure of molecules–helium clusters X{sup 4}He{sub 20} (X=HCCH and LiH) which show a marked improvement over the Trotter approximation which has a 2nd-order time step bias. We show that the 4th-order corrections of the Takahashi–Imada approximation can also be applied perturbatively to a 2nd-order simulation.

• OSTI ID: 22570195
• Journal Information: Journal of Computational Physics, Journal Name: Journal of Computational Physics Vol. 301; ISSN JCTPAH; ISSN 0021-9991
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
APPROXIMATIONS
ATOMS
COMPUTERIZED SIMULATION
MATRICES
MATRIX ISOLATION
MIXTURES
MOLECULES
MONTE CARLO METHOD
PATH INTEGRALS
PROPAGATOR
SUPERFLUIDITY