title: Is the molecular Berry phase an artifact of the Born-Oppenheimer approximation?
abstract: We demonstrate that the molecular Berry phase and the corresponding nonanalyticity in the electronic Born-Oppenheimer wave function is, in general, not a true topological feature of the exact solution of the full electron-nuclear Schrödinger equation. For a numerically exactly solvable model we show that a nonanalyticity, and the associated geometric phase, only appear in the limit of infinite nuclear mass, while a perfectly smooth behavior is found for any finite nuclear mass.
authors.affiliation: Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and Department of Chemistry, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea.
authors.forename: Seung Kyu
authors.initials: SK
authors.lastname: Min
authors.affiliation: Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and European Theoretical Spectroscopy Facility (ETSF).
authors.forename: Ali
authors.initials: A
authors.lastname: Abedi
authors.affiliation: Department of Chemistry, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea.
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Max-Planck Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany and European Theoretical Spectroscopy Facility (ETSF).
authors.forename: E K U
authors.initials: EK
authors.lastname: Gross