title: An automated integration-free path-integral method based on Kleinert's variational perturbation theory.
abstract: Based on Kleinert's variational perturbation (KP) theory [Path Integrals in Quantum Mechanics, Statistics, Polymer Physics, and Financial Markets, 3rd ed. (World Scientific, Singapore, 2004)], we present an analytic path-integral approach for computing the effective centroid potential. The approach enables the KP theory to be applied to any realistic systems beyond the first-order perturbation (i.e., the original Feynman-Kleinert [Phys. Rev. A 34, 5080 (1986)] variational method). Accurate values are obtained for several systems in which exact quantum results are known. Furthermore, the computed kinetic isotope effects for a series of proton transfer reactions, in which the potential energy surfaces are evaluated by density-functional theory, are in good accordance with experiments. We hope that our method could be used by non-path-integral experts or experimentalists as a "black box" for any given system.
authors: Department of Chemistry and Minnesota Supercomputing Institute, University of Minnesota, Smith Hall, Minneapolis, Minnesota 55455, USA. kiniu@alumni.cuhk.net
authors: Kin-Yiu
authors: KY
authors: Wong
authors: Jiali
authors: J
authors: Gao