title: Relativistic Effects on the Topology of the Electron Density.
abstract: The topological analysis of electron densities obtained either from X-ray diffraction experiments or from quantum chemical calculations provides detailed insight into the electronic structure of atoms and molecules. Of particular interest is the study of compounds containing (heavy) transition-metal elements, which is still a challenge for experiment as well as from a quantum-chemical point of view. Accurate calculations need to take relativistic effects into account explicitly. Regarding the valence electron density distribution, these effects are often only included indirectly through relativistic effective core potentials. But as different variants of relativistic Hamiltonians have been developed all-electron calculations of heavy elements in combination with various electronic structure methods are feasible. Yet, there exists no systematic study of the topology of the total electron density distribution calculated in different relativistic approximations. In this work we therefore compare relativistic Hamiltonians with respect to their effect on the electron density in terms of a topological analysis. The Hamiltonians chosen are the four-component Dirac-Coulomb, the quasi-relativistic two-component zeroth-order regular approximation, and the scalar-relativistic Douglas-Kroll-Hess operators.
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159 Augsburg, Germany, and Institut für Anorganische Chemie, Ruprechts-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Eickerling
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159 Augsburg, Germany, and Institut für Anorganische Chemie, Ruprechts-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Remigius
authors.initials: R
authors.lastname: Mastalerz
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159 Augsburg, Germany, and Institut für Anorganische Chemie, Ruprechts-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Herz
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159 Augsburg, Germany, and Institut für Anorganische Chemie, Ruprechts-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Scherer
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159 Augsburg, Germany, and Institut für Anorganische Chemie, Ruprechts-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Himmel
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zurich, Hönggerberg Campus, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland, Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159 Augsburg, Germany, and Institut für Anorganische Chemie, Ruprechts-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Reiher