Reference : Perturbed path integrals in imaginary time: Efficiently modeling nuclear quantum effe...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Computational Sciences
http://hdl.handle.net/10993/33844
Perturbed path integrals in imaginary time: Efficiently modeling nuclear quantum effects in molecules and materials
English
Poltavskyi, Igor mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
DiStasio, Robert mailto [Cornell University, Ithaca, NY 14853, United States > Department of Chemistry & Chemical Biology]
Tkatchenko, Alexandre mailto [University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit >]
14-Mar-2018
Journal of Chemical Physics
American Institute of Physics
148
10
NUCLEAR QUANTUM EFFECTS
102325
Yes (verified by ORBilu)
International
1089-7690
[en] imaginary time path integrals ; ab initio simulations ; nuclear quantum effects
[en] Nuclear quantum effects (NQE), which include both zero-point motion and tunneling, exhibit quite an impressive range of influence over the equilibrium and dynamical properties of molecules and materials. In this work, we extend our recently proposed perturbed path-integral (PPI) approach for modeling NQE in molecular systems [I. Poltavsky and A. Tkatchenko, Chem. Sci. 7, 1368 (2016)], which successfully combines the advantages of thermodynamic perturbation theory with path-integral molecular dynamics (PIMD), in a number of important directions. First, we demonstrate the accuracy, performance, and general applicability of the PPI approach to both molecules and extended (condensed-phase) materials. Second, we derive a series of estimators within the PPI approach to enable calculations of structural properties such as radial distribution functions (RDFs) that exhibit rapid convergence with respect to the number of beads in the PIMD simulation. Finally, we introduce an effective nuclear temperature formalism within the framework of the PPI approach and demonstrate that such effective temperatures can be an extremely useful tool in quantitatively estimating the “quantumness” associated with different degrees of freedom in the system as well as providing a reliable quantitative assessment of the convergence of PIMD simulations. Since the PPI approach only requires the use of standard second-order imaginary-time PIMD simulations, these developments enable one to include a treatment of NQE in equilibrium thermodynamic properties (such as energies, heat capacities, and RDFs) with the accuracy of higher-order methods but at a fraction of the computational cost, thereby enabling first-principles modeling that simultaneously accounts for the quantum mechanical nature of both electrons and nuclei in large-scale molecules and materials.
Researchers ; Professionals ; Students
http://hdl.handle.net/10993/33844
10.1063/1.5006596
http://aip.scitation.org/doi/pdf/10.1063/1.5006596
FnR ; FNR11360857 > Alexandre Tkatchenko > QUANTION > Quantum Ion Tunneling And Scattering In Layered Nanomaterials > 01/03/2017 > 29/02/2020 > 2016

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