Asbjörn M. Burow

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Scanning-tunneling microscopy and density-functional theory have been employed to identify the spatial correlation between an oxygen vacancy and the associated Ce(3+) ion pair in a defective CeO(2)(111) film. The two Ce(3+) ions can occupy different cationic shells around the vacancy. The resulting variation in the chemical environment leads to a splitting(More)
This work demonstrates that the most stable structures of even small gas-phase aggregates of cerium oxide with 2-5 cerium atoms show structural motifs reminiscent of the bulk ceria. This is different from main group and transition metal oxide clusters, which often display structural features that are distinctly different from the bulk structure. The(More)
A new formulation of resolution of identity approximation for the Coulomb term is presented, which uses atom-centered basis and auxiliary basis functions and treats molecular and periodic systems of any dimensionality on an equal footing. It relies on the decomposition of an auxiliary charge density into charged and chargeless components. Applying the(More)
An adaptive numerical integration scheme for efficient evaluation of the exchange-correlation term using localized basis functions and atom-centered grids is presented. The method treats molecules and systems with periodic boundary conditions on an equal footing. Its computational efficiency and O(N) scaling with the system size is achieved by a(More)
The charge density and its Laplacian at the Li-C and C-H bond critical points and other features of the electron density distribution of the methyl lithium crystal have been compared by density functional methods for (i) the isolated (LiCH(3))(4) tetramer or larger clusters, (ii) for quantum mechanically treated clusters in polarizable continuum model (PCM)(More)
An implementation of Kohn-Sham density functional theory within the TURBOMOLE program package with Gaussian-type orbitals (GTO) as basis functions is reported that treats molecular and periodic systems of any dimensionality on an equal footing. Its key component is a combination of density fitting/resolution of identity (DF) approximation and continuous(More)
A periodic electrostatic embedding scheme is presented that uses the periodic fast multipole method. The convergence of properties with increasing cluster size is examined for cluster models of calcium fluoride. Properties investigated are the electron density, the density of states, the electronic excitation of color centers, and energies of defect(More)
The random phase approximation (RPA) is an increasingly popular method for computing molecular ground-state correlation energies within the adiabatic connection fluctuation-dissipation theorem framework of density functional theory. We present an efficient analytical implementation of first-order RPA molecular properties and nuclear forces using the(More)
A method to compute ground state correlation energies from the random phase approximation (RPA) is presented for molecular and periodic systems on an equal footing. The supermatrix representation of the Hartree kernel in canonical orbitals is translation-symmetry adapted and factorized by the resolution of the identity (RI) approximation. Orbital expansion(More)
A full implementation of analytical energy gradients for molecular and periodic systems is reported in the TURBOMOLE program package within the framework of Kohn-Sham density functional theory using Gaussian-type orbitals as basis functions. Its key component is a combination of density fitting (DF) approximation and continuous fast multipole method (CFMM)(More)
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