Ab initio electronic structure calculations of actinide compounds have a weak point when the spin-orbit coupling is treated using a scalar-relativistic basis and the second variational method due to the poor description of the 6p states. We extend the basis set of the second variational step by including relativistic p 1/2 local orbitals for the description of the 6p states. Our results show that the additional p 1/2 local orbitals significantly improve the description of actinides.

The exact exchange of density functional theory is used to calculate the electronic structure of the antiferromagnetic (type II) phases of the transition-metal monoxides MnO, FeO, CoO, and NiO at T=0. In contrast with the local density approximation (LDA) and generalized gradient approximation, the exact exchange (combined with LDA correlation) correctly yields insulating ground states for all four compounds. The values for the band gaps and magnetic moments obtained with this parameter-free first principles method are in good agreement with the experimental data. While correlation plays a major role for the electronic structure, these results demonstrate that the mere opening of a gap in FeO and CoO is already obtained on the level of density functional theory, if the exact, multiplicative exchange potential is combined with a full potential method. State-dependent potentials are not required for obtaining a gap.

Standard normconserving pseudopotentials for the exact exchange energy functional of density functional theory exhibit a spurious long-range structure induced by the core-valence interaction. In this contribution the origin of this structure and its implications for the description of atoms, molecules, and solids is analyzed in detail. It is found that bond distances and energies obtained can be seriously in error, in particular for solids. Based on this analysis a parameter-free, self-consistent scheme for the elimination of the spurious feature is suggested. The resulting pseudopotentials predict binding properties of molecules and solids which, on average, are more accurate than those obtained with the corresponding local density approximation pseudopotentials.

Aus der Fülle metall-organischer Koordinationspolymere ragt die von Yaghi und Mitarbeitern entwickelte Stoffklasse hoch poröser basischer Zinkcarboxylate heraus.[1] Ihr Prototyp ist MOF-5 (MOF = Metal Organic Framework), in dem {Zn 4 O}-Baueinheiten über Terephthalat-Brücken zu einem Zeolith-ähnlichen, kubischen Raumnetz verknüpft sind. [2] Die von keiner anderen kristallinen Substanz übertroffenen, extrem hohen spezifischen Oberflächen [2] bis zu 4500 m 2 g À1und Porenvolumina von 0.69 cm 3 cm À3 (für MOF-177) sowie die thermische Stabilität (bis zu 350 8C) eröffnen faszinierende Perspektiven für die supramolekulare Wirt-GastChemie.[3] Anwendungen für miniaturisierte Brennstoffzellen und Gasspeicher (für H 2 , CH 4 ), als Gassensoren sowie als Trennmedien und Katalysatormaterialien, aber auch Mög-lichkeiten für die molekulare Elektronik zeichnen sich ab. [4] Ein Bericht über die quantitative Einlagerung von C 60 und großen polycyclischen Farbstoffmolekülen (z. B. Astrazon Orange R) in die Hohlräume von MOF-177-Einkristallen erregte unsere Aufmerksamkeit.[5] Sollten diese MOF-Wirtsgitter nicht ebenso effizient und selektiv auch typische metallorganische CVD-Vorstufen aufnehmen können, solange diese nur flüchtig (Gasabsorption) oder sehr gut löslich in Kohlenwasserstoffen wären und eine zum Hohlraum passen- [8] und [Au(CH 3 )(PMe 3 )] (3).[9]Die Größen-bzw. Formselektivität ist erwartungsgemäß sehr hoch. Für 2, das nur wenig mehr Raum beansprucht als 1 oder 3, findet man nur zwei statt vier eingelagerte Moleküle

Perturbation theory on the basis of the Kohn-Sham Hamiltonian leads to an implicit density functional for the correlation energy E(c). In this contribution we investigate the corresponding correlation potential v(c). It is shown that for finite systems the v(c) obtained by direct application of the optimized potential method diverges in the asymptotic region. The presence of unoccupied states, inherent in any perturbative form of E(c), is identified as the origin of this unphysical behavior. An approximate variational procedure is developed in order to avoid this difficulty. The potential resulting from this method qualitatively reproduces the shell structure of the exact atomic v(c).

Stimuli-responsive flexible metal-organic frameworks (MOFs) remain at the forefront of porous materials research due to their enormous potential for various technological applications. Here, we introduce the concept of frustrated flexibility in MOFs, which arises from an incompatibility of intra-framework dispersion forces with the geometrical constraints of the inorganic building units. Controlled by appropriate linker functionalization with dispersion energy donating alkoxy groups, this approach results in a series of MOFs exhibiting a new type of guest- and temperature-responsive structural flexibility characterized by reversible loss and recovery of crystalline order under full retention of framework connectivity and topology. The stimuli-dependent phase change of the frustrated MOFs involves non-correlated deformations of their inorganic building unit, as probed by a combination of global and local structure techniques together with computer simulations. Frustrated flexibility may be a common phenomenon in MOF structures, which are commonly regarded as rigid, and thus may be of crucial importance for the performance of these materials in various applications.

Flexible porous frameworks are at the forefront of materials research. A unique feature is their ability to open and close their pores in an adaptive manner induced by chemical and physical stimuli. Such enzyme‐like selective recognition offers a wide range of functions ranging from gas storage and separation to sensing, actuation, mechanical energy storage and catalysis. However, the factors affecting switchability are poorly understood. In particular, the role of building blocks, as well as secondary factors (crystal size, defects, cooperativity) and the role of host–guest interactions, profit from systematic investigations of an idealized model by advanced analytical techniques and simulations. The review describes an integrated approach targeting the deliberate design of pillared layer metal–organic frameworks as idealized model materials for the analysis of critical factors affecting framework dynamics and summarizes the resulting progress in their understanding and application.

Based on the density functional approach to quantum hadrodynamics a local efFective exchange potential for use in nuclear structure calculations beyond the mean-Geld approximation has been developed. For a conceptual study of the density functional technique the resulting Kohn-Sham single-particle equations have been solved for several spherical nuclei vrithin the linear cr-u model. A detailed comparison with Hartree-Fock results is given.