title: Spin Signature of Nonlocal Correlation Binding in Metal-Organic Frameworks.
abstract: We develop a proper nonempirical spin-density formalism for the van der Waals density functional (vdW-DF) method. We show that this generalization, termed svdW-DF, is firmly rooted in the single-particle nature of exchange and we test it on a range of spin systems. We investigate in detail the role of spin in the nonlocal correlation driven adsorption of H_{2} and CO_{2} in the linear magnets Mn-MOF74, Fe-MOF74, Co-MOF74, and Ni-MOF74. In all cases, we find that spin plays a significant role during the adsorption process despite the general weakness of the molecular-magnetic responses. The case of CO_{2} adsorption in Ni-MOF74 is particularly interesting, as the inclusion of spin effects results in an increased attraction, opposite to what the diamagnetic nature of CO_{2} would suggest. We explain this counterintuitive result, tracking the behavior to a coincidental hybridization of the O p states with the Ni d states in the down-spin channel. More generally, by providing insight on nonlocal correlation in concert with spin effects, our nonempirical svdW-DF method opens the door for a deeper understanding of weak nonlocal magnetic interactions.
authors.affiliation: Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27106, USA.
authors.forename: T
authors.initials: T
authors.lastname: Thonhauser
authors.affiliation: Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27106, USA.
authors.forename: S
authors.initials: S
authors.lastname: Zuluaga
authors.affiliation: Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27106, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Arter
authors.affiliation: Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.|Centre for Materials Science and Nanotechnology (SMN), University of Oslo, 0316 Oslo, Norway.
authors.forename: K
authors.initials: K
authors.lastname: Berland
authors.affiliation: Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Schröder
authors.affiliation: Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Hyldgaard