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We implemented and applied a hybrid approach for modeling the solvation of molecules where we combined a three-dimensional reference interaction site model (3D RISM) with quantum mechanical (QM) calculations of the solute. The electrostatic potential induced by the solute is derived directly from its electron density. For neutral solutes, we analyzed the accuracy of calculated solvation free energies which is mainly determined by the cavity formation energy. In an aqueous medium the solute electronic structure relaxation also has a noticeable influence on the results of SCF-RISM calculations. We apply a known partial molar volume correction for which we give an alternative interpretation. The results of this hybrid model agree well with experiment and results of a polarizable continuum model (PCM). As a model with an atomic solvent representation, RISM accounts for the effect of discrete hydrogen bonds which in PCM models are included on average only.

We report an implementation of the three-dimensional reference interaction site model (3D RISM) that in particular addresses the treatment of the long-range Coulomb field of charged species, represented by point charges and/or a distributed charge density. A comparison of 1D and 3D results for atomic ions demonstrates a reasonable accuracy, even for a moderate size of the unit cell and a moderate grid resolution. In an application to uranyl complexes with 4-6 explicit aqua ligands and an implicit bulk solvent modeled by RISM, we show that the 3D technique is not susceptible to the deficiencies of the 1D technique exposed in our previous work [Li, Matveev, Krüger, Rösch, Comp. Theor. Chem. 2015, 1051, 151]. The 3D method eliminates the artificial superposition of explicit aqua ligands and the RISM medium and predicts essentially the same values for uranyl and uranyl-water bond lengths as a state-of-the-art polarizable continuum model. With the first solvation shell treated explicitly, the observables are nearly independent of the order of the closure relationship used when solving the set of integral equations for the various distribution functions. Furthermore, we calculated the activation barrier of water exchange with a hybrid approach that combines the 3D RISM model for the bulk aqueous solvent and a quantum mechanical description (at the level of electronic density functional theory) of uranyl interacting with explicitly represented water molecules. The calculated result agrees very well with experiment and the best theoretical estimates.

We apply the one-dimensional reference interaction site model (RISM) to the solvation of uranyl in water. Uranyl aqua complexes with 4–6 explicit water ligands and an implicit water solvent, modeled by RISM to represent the further solvent environment, have been examined. The interaction of explicitly represented atoms of the aqua complexes are treated either by molecular mechanics or density functional theory, to build the free energy functional. A comparison of solvation energies and geometries of the aqua complexes for different numbers of explicit water ligands at the local minimum of the free energy surface indicate the interchangeability of explicit and implicit solvent models. Consequently the solvation energy is rather independent of the number of aqua ligands of the uranyl complex used as solute model, in contrast to results of a polarizable continuum model of solvation. For uranyl with four and five explicit water ligands in the first solvation shell we determined only a minor preference for the latter, in agreement with experiment. Other computational approaches tend to overestimate this preference.

Parallel implementations of quantum chemistry programs targeting supercomputers are challenging applications of dynamic load balancing algorithms. The implementation of work stealing (WS) algorithms is discussed and their usefulness is demonstrated. Evaluation of the four-center integrals of a Cu10 cluster requires 25 core-hours overall, achieving 88% efficiency with simple WS for 2048 cores, and 97% with task presorting based on a cost estimate. Limitations of cost sorting become noticeable for larger systems. When spatial symmetry is exploited together with integral screening, bundling the original tasks yields an efficiency of 98% for Cu79 in Oh symmetry on 512, 1204, and 2048 cores. The advantage of WS algorithms described in this work is not limited to the evaluation of four-center integrals. © 2014 Wiley Periodicals, Inc.

To assess various ionic-core approximations we carried out density functional calculations on a series of octahedral palladium and gold model clusters M n with n = 13–147. We compared results for average bond lengths, cohesive energies, vertical ionization potentials, and electron affinities to the corresponding all-electron scalar relativistic results. We used extrapolated bulk values to compare with experiments. The results of the projector-augmented wave method agree best with the all-electron results. When modeling palladium–gold nanoalloy particles, one should keep in mind that current ECP or PAW modeling of palladium moieties appears to be more accurate than modeling of gold species.

Effective brand management is vital for building the necessary bond between an organization and its consumers. LG Electronics serves as a notable example of a global company that effectively communicates its brand in diverse markets. This study focuses on the remarkable case of LG Electronics' LCD Monitors and plasma TV screens to highlight critical elements of effective brand management across the different cultural contexts of the United Kingdom and the Russian Federation. The findings reveal that LG Electronics standardizes part of its logo and slogan in both cultures. However, the company uses different communication strategies in the UK and Russia. Specifically, LG uses a differentiated strategy with regard to both the visual and the written components of its high-involvement print advertisements. However, it uses a mixed strategy of standardized visual and differentiated written components in its low-involvement TV advertisements. These differences in LG Electronics' print and TV advertisement strat...

Transition state discovery via application of string methods has been researched on two fronts. The first front involves development of a new string method, named the Searching String method, while the second one aims at estimating transition states from a discretized reaction path. The Searching String method has been benchmarked against a number of previously existing string methods and the Nudged Elastic Band method. The developed methods have led to a reduction in the number of gradient calls required to optimize a transition state, as compared to existing methods. The Searching String method reported here places new beads on a reaction pathway at the midpoint between existing beads, such that the resolution of the path discretization in the region containing the transition state grows exponentially with the number of beads. This approach leads to favorable convergence behavior and generates more accurate estimates of transition states from which convergence to the final transition states occurs more readily. Several techniques for generating improved estimates of transition states from a converged string or nudged elastic band have been developed and benchmarked on 13 chemical test cases. Optimization approaches for string methods, and pitfalls therein, are discussed.

Invoking a DFT + U approach, we explored self-interaction artifacts in results from Kohn–Sham (KS) density functional calculations on the geometry and the vibrational frequencies of uranyl monohydroxide and the corresponding tetra-aqua complex. Exchange–correlation functionals based on the local density approximation (LDA) and the generalized-gradient approximation (GGA) predict equilibrium geometries for [UO2(OH)]+ that deviate from the results of hybrid DFT calculations and high-level wavefunction-based methods such as CCSD(T). LDA + U and GGA + U functionals with corrections for the insufficient localization of the U 5f shell yield better agreement, in particular for the angle U-Oh-H. At the LDA level, a linear coordination of the OH ligand results; with the +U correction, the angle U-Oh-H is reduced by ~35°, in good agreement with CCSD(T) results. At the GGA level, the bending angle is changed by ~20°. This relatively strong self-interaction artifact is traced back to a spurious π interaction between U 5f and O(p) orbitals which is less pronounced in the presence of further (aqua) ligands.

Using the LCGTO-DFT + U methodology, we analyze the potential effect of self-interaction artifacts in standard Kohn-Sham (KS) density functional calculations on geometries, vibrational frequencies, and bonding for the example of the uranyl (VI) dication, both without and with explicit aqua ligands. We attribute the bent structure of the uranyl moiety in the penta-aqua complex to the limited accuracy of the Coulomb interaction of the U 5f orbitals afforded by common local or gradient-corrected exchange-correlation functionals. In particular, with scalar relativistic, all-electron Douglas-Kroll-Hess calculations we demonstrate that the distorted geometry of the uranyl penta-aqua complex is essentially rectified by the inclusion of a small positive on-site repulsion parameter. U(eff), for the 5f shell of the uranium atom. (C) 2010 Elsevier B.V. All rights reserved.

This article examines the effectiveness of the team infomercial assignment as an active learning tool in undergraduate courses. The structure and three phases of the team infomercial assignment, as well as student evaluations and feedback, are presented. We investigated student experiences working on the team infomercial assignment, the common challenges that students faced, and the effective approaches to implementing this assignment in higher education settings. Results show that the team infomercial assignment is instrumental in developing analytical and presentation skills, effective teamwork, reflective learning, and the application of knowledge and skills in future learning. We conclude that the team infomercial assignment is clearly of value to students and provides a benchmark example for instructors interested in employing active learning approaches.

Using the DFT + U methodology with a localized basis set, we studied the role of Lu 4f orbitals in the bonding of LuF3. We carried out scalar relativistic all-electron Douglas-Kroll-Hess DFT calculations of geometry, atomization energy, and vertical ionization potentials without and with the Hubbard term. The on-site repulsion parameter U-eff for Lu 4f orbitals was estimated from reference atomic data. With U-eff > 0, atomic localization of the valence 4f-like molecular orbitals is recovered, thus removing the spurious mixing of Lu 4f and F 2p orbitals present in standard Kohn-Sham calculations, while the molecular properties of LuF3 remained unchanged. (C) 2008 Elsevier B. V. All rights reserved.

Experimental findings imply that edge sites (and other defects) on Pd nanocrystallites exposing mainly (111) facets in supported model catalysts are crucial for catalyst modification via deposition of CH(x) (x = 0-3) byproducts of methanol decomposition. To explore this problem computationally, we applied our recently developed approach to model realistically metal catalyst particles as moderately large three-dimensional crystallites. We present here the first results of this advanced approach where we comprehensively quantify the reactivity of a metal catalyst in an important chemical process. In particular, to unravel the mechanism of how CH(x) species are formed, we carried out density functional calculations of C-O bond scission in methanol and various dehydrogenated intermediates (CH3O, CH2OH, CH2O, CHO, CO), deposited on the cuboctahedron model particle Pd79. We calculated the lowest activation barriers, approximately 130 kJ mol(-1), of C-O bond breaking and the most favorable thermodynamics for the adsorbed species CH3O and CH2OH which feature a C-O single bond. In contrast, dissociation of adsorbed CO was characterized as negligibly slow. From the computational result that the decomposition products CH3 and CH2 preferentially adsorb at edge sites of nanoparticles, we rationalize experimental data on catalyst poisoning.

We present a general strategy for interpreting optical spectra of interacting systems on the basis of linear-response time-dependent density functional theory (TDDFT) calculations. For this purpose, we combined a natural transition orbitals (NTO) analysis with a fragment molecular orbital (FMO) analysis. The NTO transformation allows one to identify leading contributions of particle-hole excitations in the spectral bands, whereas the FMO analysis characterizes each pair in terms of (leading) contributions of the corresponding fragments. We applied this procedure to assign and characterize optical transitions of coinage metal dimers M2 (M = Cu, Ag, Au) adsorbed at regular oxygen sites of MgO(001) as well as at oxygen vacancies, Fs and F. The TDDFT calculations were carried out at the generalized-gradient level on structures that had been obtained with cluster models embedded in an elastic polarizable environment. The combined NTO and FMO results allowed us to analyze the spectra both qualitatively and quantitatively. The qualitative results agree very well with a previous assignment carried out by our group (Bosko et al., J Phys Chem A, 2007, 111, 6870), whereas the present approach yields a straightforward and transparent quantitative characterization of the main spectral bands. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008

This article investigates nostalgia in post-socialist Russia from a consumer behavior perspective. The research includes the following components: 1) an overview of nostalgia and nostalgia proneness as a personality trait among Russians in the context of recent societal changes, 2) an analysis of four categories of nostalgia (personal, interpersonal, cultural, and virtual) and themes in nostalgia experiences provided by Russian respondents, and 3) a discussion of specific stimuli and advertising content in the Russian marketplace designed to evoke individual and collective nostalgia. The major nostalgia themes—specifically, the break-up of the Soviet Union, nature, and food—identified in the Russian responses are related to advertising and marketing elements for Russian products. The article also discusses the implications of consumer nostalgia for marketing and advertising strategy in the post-socialist Russian economy.

Polarization-resolved optical spectra of coinage metal monomers and dimers Mn (M = Cu, Ag, Au; n = 1, 2) at ideal O2- sites of MgO(001) as well as at oxygen vacancies, Fs and Fs+, of that surface were established using a computational approach based on linear response time-dependent density functional theory. Calculations were performed for structures determined by applying a generalized-gradient density functional method to cluster models embedded in an elastic polarizable environment. This embedding scheme provides an accurate description of substrate relaxation and long-range electrostatic interaction. We compared the optical properties of adsorbed atoms and dimers with those of the corresponding gas-phase species and we systematically analyzed trends among congeners.

Starting from a matrix representation of the modified Dirac equation, we offer an alternative approach to the Douglas–Kroll–Hess (DKH) protocol, specifically for the popular decoupling of electronic and positronic degrees of freedom to second-order in the potential. Then we use that approach for a convenient analysis of response properties. We discuss details of the linear and quadratic response of the DKH Hamiltonian to a geometric distortion encountered in calculations of first- and second-order derivatives of the energy. We present an implementation of analytic force constants in a quasi-relativistic (scalar) model constructed by the commonly used DKH transformation of second order in the nuclear potential only. We demonstrate the performance of the method by a comparison to the effective core potential method, using two isomers of the cluster Ir4 and aqua complexes of the uranyl dication, UO(H2O)n (n = 3,…6) as examples. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007

Using various two-step strategies, we examined how to accurately locate transition states (TS) of reactions using the example of eight reactions at metal surfaces with 14–33 moving atoms. These procedures combined four path-finding methods for locating approximate TS structures (nudged elastic band, standard string, climbing image string, and searching string, using a conjugate gradient or a modified steepest-descent method for optimization and two types of coordinate systems) with subsequent local refinement by two dimer methods. The dimer-Lanczos variant designed for this study required on average 20% fewer gradient calls than the standard dimer method. During the path finding phase, using mixed instead of Cartesian coordinates reduced the numbers of gradient calls on average by an additional 21%, while using a modified steepest-descent method improved that key efficiency criterion on average by 13%. For problematic cases we suggest strategies especially adapted to the problem at hand.

Starting with the hypothesis that cross cultural communication competence affects the performance of multicultural teams, we employed the Cross Cultural Communication Competence Model to compare American and Russian managers working in multicultural teams. We collected data from 124 upper and middle managers in the United States and the Russian Federation by administering the cross cultural communication competence and the high-performance team questionnaires. Drawing from proven conceptual cultural orientations suggested by Hall, Hofstede, and Javidan and House, we examined how national culture affects team members’ perceptions of cross cultural communication competence. The confirmed hypothesized relationship and salient effects of national culture on cross cultural communication competence led to theoretical and practical implications for multicultural organizational settings.

Managers working in multinational companies carry out their organizational goals through multicultural teams. Performance of multicultural teams can be examined from an intercultural communication perspective. Executives, managers, management consultants, and educators interested in improving multicultural team performance need to know about intercultural competence and how it affects team performance. This article provides a working definition of high‐performance multicultural teams and outlines the challenges multicultural teams face. These definitions along with extensive interview data and detailed self‐reports of American and Russian managers working in multicultural teams emphasize the high importance of intercultural competence in improving the performance of these teams. This article also serves to highlight the characteristics of high‐performance multicultural teams, the common challenges of multicultural teams, and the sources of these challenges.

We investigated Boettger’s screened nuclear potential approximation for the spin–orbit interaction (SNSO) in the context of the Douglas–Kroll approach to relativistic Kohn–Sham theory. We extended the approximation to second-order terms and evaluated it for various atomic and molecular properties (spin–orbit splittings, g -tensor shifts, bond lengths, vibrational frequencies and binding energies) and compared the SNSO results with those of a self-consistent relativistic treatment of the electron–electron (ee) interaction. The SNSO approximation is comparable in computational effort to the model based on the nuclear potential only, but delivers molecular results that agree well with those of the more exact ee treatment.

Incorporation of relativistic effects into all-electron density functional (DF) calculations via scalar relativistic corrections to the kinetic energy and the nuclear attraction energy has become rather common. On the other hand, a self-consistent treatment of the spin–orbit interaction and relativistic corrections to the electron–electron interaction (or both simultaneously) requires substantially more computational effort. We present an extension of the Douglas–Kroll approach to the Dirac–Kohn–Sham problem that accounts for relativistic corrections to the Hartree potential and permits a self-consistent treatment of spin–orbit interaction. To construct computationally efficient approximations, we exploit the electron charge density fitting scheme with an auxiliary basis set. These approximate schemes introduce effects of the relativistic transformation of the Hartree part of the electron–electron interaction, but leave the (smaller) exchange-correlation contributions untransformed. These approximations w...

We present a novel scheme to calculate electronic g-tensor values of doublet-state systems within a density functional method and discuss the implementation and results of first applications. The method employs two-component eigenfunctions of the Kohn−Sham equation where spin−orbit effects are taken into account self-consistently. Therefore, the g-tensor can be treated as first-order property with respect to the perturbation by external magnetic field alone. The Zeeman energy splitting, an inherently relativistic effect, is naturally and transparently determined by the two-component ground-state wave function (Kramers doublet) without invoking virtual states. Abandoning the widely accepted perturbative treatment of the spin−orbit term makes the present method also applicable to molecular systems with considerable spin−orbit interaction. Conceivable improvements of the method performance are proposed and discussed.

Adsorption of Cu, Ni, Ag, and Pd atoms on F s and F + s oxygen vacancy sites as well as on regular O 2− centers of the MgO(001) surface has been studied by means of gradient-corrected density functional calculations using cluster models embedded in a matrix of model potentials and point charges. Scalar relativistic effects have been taken into account for adsorbed Ag and Pd species. The electronic structure, geometric parameters, and binding energies of the adsorption complexes have been calculated and analyzed with reference to the electronic properties of the vacancy sites and the metal atoms in question. For all adsorbates considered, adsorption is found to be stronger on F s sites by 1–2.4 eV compared with regular O 2− sites, with Pd and Ni forming the most stable complexes. On the F + s site the single valence electron of Cu and Ag atoms couples with an unpaired electron of the vacancy forming a covalent bond. As a result the adsorption energy of these atoms on F + s is by more than 1 eV stronger than on the F s sites; on the other hand, the adsorption energies of Ni and Pd are reduced on F + s by 0.5 eV and 1.3 eV respectively. The whole series of M/F + s complexes is characterized by rather uniform values of adsorbate–substrate distances (1.5–1.7 A) and adsorption energies (2.2–2.6 eV).

We have implemented the generalized gradient approximation (GGA) exchange–correlation functional suggested by Perdew, Burke, and Ernzerhof (PBE) and two of its recent revisions, revPBE and RPBE, in the program ParaGauss, which is a new version of the LCGTO-FF (fitting function) approach designed for parallel computers. With these new functionals, we investigated a test suite of 19 small molecules as well as the transition-metal carbonyls of Cr, Fe, and Ni using very flexible Gaussian-type orbital (GTO) basis sets. Both revised PBE functionals yield very similar results for the atomization energies of small molecules, improved over those obtained with conventional GGAs (BP, PW91, PBE) as judged by the average absolute error (5 kcal/mol reduced from 8 kcal/mol). Atomization energies of revised PBE functionals are on the average 7 kcal/mol smaller than those of conventional GGAs, consistent with an average bond elongation by about 0.006 A relative to these GGAs. Revised PBE functionals yield bond distances on average 0.016 A longer than experiment. With revised PBE functionals, the first carbonyl dissociation energies of Cr(CO)6, Fe(CO)5, and Ni(CO)4 are calculated in excellent agreement with experiment whereas structures are calculated very similar to those of conventional GGAs. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 75: 863–873, 1999

The interaction of square-planar M 4 clusters (M=Ag, Cu, Ni, Pd) with the ideal MgO(001) surface has been investigated using a gradient-corrected density functional (DF) method and substrate model clusters for adsorption sites in the vicinity of O 2− centers. Polarization of the adsorbed metal clusters due to the surface electric field provides an important contribution to metal–oxide bonds. No significant elongation of the M–M bond relative to free square-planar M 4 species is calculated in adsorbed clusters, with Pd 4 exhibiting the largest expansion of 0.1 A. At variance with Ni and Cu, for Pd and Ag only a moderate energy expense is required to sufficiently lengthen the M–M bonds such that the atoms are put in their most favorable adsorption positions on MgO close to surface O 2− anions.

Density functional theory (DFT) provides some of the most important methods used in computational theory today. They allow one to determine the electronic structure of finite chemical systems, be they molecules or clusters, using a quantum-mechanical model, and exposes, thus, the great majority of the systems’ properties relevant to chemical applications. However, the numerical treatment of large chemical systems proves to be expensive, requiring elaborate parallelisation strategies.This paper presents two recent developments which aim at improving the parallel scalability of the quantum chemistry code ParaGauss. First, we introduce a new Fortran interface to parallel matrix algebra and its library implementation. This interface specifies a set of distributed data objects, combined with a set of linear algebra operators. Thus, complicated algebraic expressions can be expressed efficiently in pseudo-mathematical notation, while the numerical computations are carried out by back-end parallel routines. This technique is evaluated on relativistic transformations, as implemented in ParaGauss.The second development addresses the solution of the generalized matrix eigenvalue problem—an inherent step in electronic structure calculations. In the case the symmetry of a molecule is exploited, pertinent matrices expose a block-diagonal structure which makes the efficient use of existing parallel eigenvalue solvers difficult. We discuss a technique that uses a malleable parallel task scheduling (MPTS) algorithm for scheduling instances of parallel ScaLAPACK-routines on the available processor resources. This technique significantly improves the parallel performance of this numerical step, reducing the corresponding execution time to below 1 s in most applications considered.

We suggest a quasi‐relativistic model for molecular electronic structure calculations obtained by an atomic ansatz for the relativistic projection transformation. With such a choice, the projection transformation becomes both transferable and independent of the geometry. The formulation is flexible with regard to the choice of the projection transformation. We employ the free‐particle Foldy–Wouthuysen and the Douglas–Kroll second‐order variants for the projection coefficients. First results for the diatomic molecules AuH, AuCl, and Au2 and two structural isomers of Ir4 suggest the new approximate method as an efficient and accurate replacement for the conventional transformation.

By using a set of model reactions, we estimated the heat of formation of gaseous UO2(2+) from quantum-chemical reaction enthalpies and experimental heats of formation of reference species. For this purpose, we performed relativistic density functional calculations for the molecules UO2(2+), UO2, UF6, and UF5. We used two gradient-corrected exchange-correlation functionals (revised Perdew-Burke-Ernzerhof (PBEN) and Becke-Perdew (BP)) and we accounted for spin-orbit interaction in a self-consistent fashion. Indeed, spin-orbit interaction notably affects the energies of the model reactions, especially if compounds of U(IV) are involved. Our resulting theoretical estimates for delta fH(o)0 (UO2(2+)), 365+/-10 kcal mol(-1) (PBEN) and 370+/-12 kcal mol(-1) (BP), are in quantitative agreement with a recent experimental result, 364+/-15 kcal mol(-1). Agreement between the results of the two different exchange-correlation functionals PBEN and BP supports the reliability of our approach. The procedure applied offers a general means to derive unknown enthalpies of formation of actinide species based on the available well-established data for other compounds of the element in question.

The quantum chemistry software ParaGauss, which implements various density functional methods to determine the electronic structure of molecular systems, has been ported to and optimized for the use on the Hitachi SR8000 supercomputer platform at Leibniz Rechenzentrum Munchen. The effort focused on tuning the code and extending it by methods that allow the simulation of molecules in an environment, e.g., in solution or adsorbed at a solid surface or in a zeolite cavity.

Single d-metal atoms on oxygen defects F(s) and F(s+) of the MgO(001) surface were studied theoretically. We employed an accurate density functional method combined with cluster models, embedded in an elastic polarizable environment, and we applied two gradient-corrected exchange-correlation functionals. In this way, we quantified how 17 metal atoms from groups 6-11 of the periodic table (Cu, Ag, Au; Ni, Pd, Pt; Co, Rh, Ir; Fe, Ru, Os; Mn, Re; and Cr, Mo, W) interact with terrace sites of MgO. We found bonding with F(s) and F(s+) defects to be in general stronger than that with O2- sites, except for Mn-, Re-, and Fe/F(s) complexes. In M/F(s) systems, electron density is accumulated on the metal center in a notable fashion. The binding energy on both kinds of O defects increases from 3d- to 4d- to 5d-atoms of a given group, at variance with the binding energy trend established earlier for the M/O2- complexes, 4d3d5d. Regarding the evolution of the binding energy along a period, group 7 atoms are slightly destabilized compared to their group 6 congeners in both the F(s) and F(s+) complexes; for later transition elements, the binding energy increases gradually up to group 10 and finally decreases again in group 11, most strongly on the F(s) site. This trend is governed by the negative charge on the adsorbed atoms. We discuss implications for an experimental detection of metal atoms on oxide supports based on computed core-level energies.

We elaborate the two-component Douglas-Kroll reduction of the Dirac-Kohn-Sham problem of relativistic density-functional theory as introduced by Matveev and R�sch [J. Chem. Phys. 118, 3997 (2003)]. That method retains corrections to the Coulomb self-interaction (or Hartree) term of the energy functional that are due to the picture change. Using analytic expressions for the matrix elements, one is able to abandon the resolution of the identity approach for a crucial step of the relativistic transformation. Thus, a major source of uncertainties of the method is eliminated because basis sets no longer have to be extended by functions of higher angular momentum, previously required to ensure kinetic balance. This approach also relies on the electron charge-density fitting scheme via an auxiliary basis set. An efficient approximate implementation results if one restricts the relativistic transformation to the spherically symmetric atom-centered auxiliary functions. It provides accurate results while simplifying greatly the expressions for the matrix elements of the relativistically transformed operators and significantly reducing the computational effort. We demonstrate the performance of the method for the fine structure of one-electron levels of the Hg atom, the g -tensor shifts of N O2, and the properties of the diatomic molecules Bi2, Pb2, PbO, and TlH. ? 2005 American Institute of Physics.

We review the Douglas-Kroll-Hess (DKH) approach to relativistic density functional calculations for molecular systems, also in comparison with other two-component approaches and four-component relativistic quantum chemistry methods. The scalar relativistic variant of the DKH method of solving the Dirac-Kohn-Sham problem is an efficient procedure for treating compounds of heavy elements including such complex systems as transition metal clusters, adsorption complexes, and solvated actinide compounds. This method allows routine all-electron density functional calculations on heavy-element compounds and provides a reliable alternative to the popular approximate strategy based on relativistic effective core potentials. We discuss recent method development aimed at an efficient treatment of spin-orbit interaction in the DKH approach as well as calculations of g tensors. Comparison with results of four-component methods for small molecules reveals that, for many application problems, a two-component treatment of spin-orbit interaction can be competitive with these more precise procedures.

We suggest an approximate relativistic model for economical all-electron calculations on molecular systems that exploits an atomic ansatz for the relativistic projection transformation. With such a choice, the projection transformation matrix is by definition both transferable and independent of the geometry. The formulation is flexible with regard to the level at which the projection transformation is approximated; we employ the free-particle Foldy-Wouthuysen and the second-order Douglas-Kroll-Hess variants. The (atomic) infinite-order decoupling scheme shows little effect on structural parameters in scalar-relativistic calculations; also, the use of a screened nuclear potential in the definition of the projection transformation shows hardly any effect in the context of the present work. Applications to structural and energetic parameters of various systems (diatomics AuH, AuCl, and Au(2), two structural isomers of Ir(4), and uranyl dication UO(2) (2+) solvated by 3-6 water ligands) show that the atomic approximation to the conventional second-order Douglas-Kroll-Hess projection (ADKH) transformation yields highly accurate results at substantial computational savings, in particular, when calculating energy derivatives of larger systems. The size-dependence of the intrinsic error of the ADKH method in extended systems of heavy elements is analyzed for the atomization energies of Pd(n) clusters (n/=116).

In recent years, fast growth in the development and application of e-business technologies has generated vast interest among practising managers and management scholars in inventory database management. E-business technologies enable an inventory manager to make coordinated decisions on the basis of regularly updated and timely ordered information. The dynamic features of the inventory items and inventory locations make a rationally organised time schedule of regular and irregular updates for inventory databases difficult. Using a game theory strategy of optimal regular updates for dynamic databases can significantly lower costs associated with the database update process. This article describes an internet-based solution of creation, maintenance, update, and query of a computerised inventory database for inventory items and their locations with time-dependent (dynamic) and time-independent (static) attributes. Further research opportunities in inventory database management using e-business applications are discussed.