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The iron(III) complexes [Fe(H2O)n(OH)m]3−m (n + m = 5, 6, m ≤ 3) and corresponding proton transfer reactions are studied with total energy calculations, the nudged elastic band (NEB) method, and molecular dynamics (MD) simulations using ab initio and a modification of reactive force field potentials, the ReaxFF-AQ potentials, based on the implementation according to Böhm et al. [J. Phys. Chem. C 120, 10849–10856 (2016)]. Applying ab initio potentials, the energies for the reactions [Fe(H2O)n(OH)m]3−m + H2O → [Fe(H2O)n−1(OH)m+1]2−m + H3O+ in a gaseous environment are in good agreement with comparable theoretical results. In an aqueous (aq) or alkaline environment, with the aid of NEB computations, respective minimum energy paths with energy barriers of up to 14.6 kcal/mol and a collective transfer of protons are modeled. Within MD simulations at room temperature, a permanent transfer of protons around the iron(III) ion is observed. The information gained concerning the geometrical and energetic properties of water and the [Fe(H2O)n(OH)m]3−m complexes from the ab initio computations has been used as reference data to optimize parameters for the O–H–Fe interaction within the ReaxFF-AQ approach. For the optimized ReaxFF-AQ parameter set, the statistical properties of the basic water model, such as the radial distribution functions and the proton hopping functions, are evaluated. For the [Fe(H2O)n(OH)m]3−m complexes, it was found that while geometrical and energetic properties are in good agreement with the ab initio data for gaseous environment, the statistical properties as obtained from the MD simulations are only partly in accordance with the ab initio results for the iron(III) complexes in aqueous or alkaline environments. [ABSTRACT FROM AUTHOR]

People in a changing environment must decide between exploiting options they currently favor and exploring alternative options that provide additional information about the state of the environment. For example, drivers must decide between purchasing gas at their currently favored station (i.e., exploit) or risk a fruitless trip to another station to evaluate whether the price has been lowered since the last visit. Previous laboratory studies on exploratory choice have found that people choose strategically and explore alternative options when it is more likely that the relative value of competing options has changed. Our study extends this work by considering how global trends (which affect all options equally) influence exploratory choice. For example, during an economic crisis, global gas prices may increase or decrease at all stations, yet consumers should still explore strategically to find the best option. Our research question is whether people can maintain effective exploration strategies in the presence of global trends that are irrelevant in that they do not affect the relative value of choice options. We find that people explore effectively irrespective of global trends.

Cyanoborane adducts of the Lewis acids B(CN)3, BF(CN)2, and BH(CN)2 with pyridine and 4‐cyanopyridine have been obtained in high yields. The syntheses were accomplished by oxidation of the readily available potassium salts of the cyano(hydrido)borate anions [BH(CN)3]− (MHB), [BFH(CN)2]− (FHB), and [BH2(CN)2]− (DHB) with bromine in the presence of the respective pyridine derivative C5H5N or 4‐CN‐C5H4N as starting material. All six cyanoborane adducts have been characterized by NMR and vibrational spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. The reduction of the cyanoborane adducts has been investigated by cyclic voltammetry and the Lewis acidity of the different cyanoboranes has been assessed using the Gutmann‐Beckett method. Selected experimental data and trends are compared to theoretical ones, for example fluoride ion affinities (FIAs). [ABSTRACT FROM AUTHOR]

The synthesis and detailed characterization of low-viscosity room-temperature ionic liquids (RTILs) and [BnPh3P]+ salts with the cyano(fluoro)borate anions [BF(CN)3]− (MFB), [BF2(CN)2]− (DFB), and [BF3(CN)]− as well as the new mixed-substituted anion [BFH(CN)2]− (FHB) is described. The RTILs with [EMIm]+ or [BMPL]+ as countercations were obtained in yields of up to 98% from readily available alkali metal salts and in high purities that allow application in electrochemical devices. Trends in thermal stability, melting and freezing behavior, density, electrochemical stability, dynamic viscosity, specific conductivity and ion diffusivity have been assessed and compared to those of the related tetracyanoborate- and cyano(hydrido)borate-RTILs. The crystal structure analysis of the [BnPh3P]+ salts of [BFn(CN)4−n]− (n = 0–4), [BHn(CN)4−n]− (n = 1–3) and [BFH(CN)2]− provided experimental access to anion volumina that together with ion molecular mass, electrostatic potential, shape and chemical stability have been correlated to physicochemical properties. In addition, the cytotoxicity of the [EMIm]+-ILs and potassium or sodium salts was studied. [ABSTRACT FROM AUTHOR]

Salts of the tetrakis(pentafluoroethyl)aluminate anion [Al(C2F5)4]− were obtained from AlCl3 and LiC2F5. They were isolated with different counter‐cations and characterized by NMR and vibrational spectroscopy and mass spectrometry. Degradation of the [Al(C2F5)4]− ion was found to proceed via 1,2‐fluorine shifts and stepwise loss of CF(CF3) under formation of [(C2F5)4−nAlFn]− (n=1–4) as assessed by NMR spectroscopy and mass spectrometry and supported by results of DFT calculations. In addition, the [(C2F5)AlF3]− ion was structurally characterized. [ABSTRACT FROM AUTHOR]

Multinomial modeling--a methodology that can be used to measure and study cognitive processes--is discussed, and applications are presented. This statistically based technique involves estimating hypothetical parameters that represent the probabilities of unobservable cognitive events and is compatible with computational theories of cognition. (SLD)

The incorporation of xenobiotics into soil, especially via covalent bonds or sequestration has a major influence on the environmental behavior including toxicity, mobility, and bioavailability. The incorporation mode of 4-chloro-2-methylphenoxyacetic acid (MCPA) into organo-clay complexes has been investigated under a low (8.5 mg MCPA/kg soil) and high (1000 mg MCPA/kg soil) applied concentration, during an incubation period of up to 120 days. Emphasis was laid on the elucidation of distinct covalent linkages between non-extractable MCPA residues and humic sub-fractions (humic acids, fulvic acids, and humin). The cleavage of compounds by a sequential chemical degradation procedure (OH-, BBr3, RuO4, TMAH thermochemolysis) revealed for both concentration levels ester/amide bonds as the predominate incorporation modes followed by ether linkages. A possible influence of the soil microbial activity on the mode of incorporation could be observed in case of the high level samples. Structure elucidation identified MCPA as the only nonextractable substance, whereas the metabolite 4-chloro-2-methylphenol was additionally found as bioavailable and bioaccessible compound. [ABSTRACT FROM AUTHOR]

People in a changing environment must decide between exploiting options they currently favor and exploring alternative options that provide additional information about the state of the environment. For example, drivers must decide between purchasing gas at their currently favored station (i.e., exploit) or risk a fruitless trip to another station to evaluate whether the price has been lowered since the last visit. Previous laboratory studies on exploratory choice have found that people choose strategically and explore alternative options when it is more likely that the relative value of competing options has changed. Our study extends this work by considering how global trends (which affect all options equally) influence exploratory choice. For example, during an economic crisis, global gas prices may increase or decrease at all stations, yet consumers should still explore strategically to find the best option. Our research question is whether people can maintain effective exploration strategies in the presence of global trends that are irrelevant in that they do not affect the relative value of choice options. We find that people explore effectively irrespective of global trends. [ABSTRACT FROM AUTHOR]

The frequency-dependent dielectric function and the second-order polarizability tensor of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained from density-functional theory. The subsequent application of the G W approximation to account for quasiparticle effects and the solution of the Bethe-Salpeter equation for the stoichiometric material yield a dielectric function that slightly overestimates the absorption onset and the oscillator strength in comparison with experimental measurements. Calculations at the level of the independent-particle approximation indicate that these deficiencies are, at least, partially related to the neglect of intrinsic defects typical for the congruent material. The second-order polarizability calculated within the independent-particle approximation predicts strong nonlinear coefficients for photon energies above 1.5 eV. The comparison with measured data suggests that the inclusion of self-energy effects in the nonlinear optical response leads to a better agreement with experiments. The intrinsic defects of congruent samples reduce the optical nonlinearities, in particular, for the 21 and 31 tensor components, further improving the agreement between experiments and theory. [ABSTRACT FROM AUTHOR]

Atomistic simulations in the framework of the density functional theory have been used to model morphologic and vibrational properties of lithium niobate–lithium tantalate mixed crystals as a function of the [Nb]/[Ta] ratio. Structural parameters such as the crystal volume and the lattice parametersaandcvary roughly linearly from LiTaO3to LiNbO3, showing only minor deviations from the Vegard behavior. Ourab initiocalculations demonstrate that the TO1, TO2and TO4vibrational modes become harder with increasing Nb concentration. TO3becomes softer with increasing Nb content, instead. Furthermore, the investigated zone centerA1-TO phonon modes are characterized by a pronounced stoichiometry dependence. Frequency shifts as large as 30 cm−1are expected as the [Nb]/[Ta] ratio grows from 0 to 1. Therefore, spectroscopic techniques sensitive to theA1modes (such as Raman spectroscopy), can be employed for a direct and non-destructive determination of the crystal composition. [ABSTRACT FROM AUTHOR]

Ab-initiomethods are applied to investigate the electronic and optical properties of lithium niobate-tantalate mixed crystals. Thereby the GW approach based on the electronic structure obtained within density functional theory is used to obtain the electron band structure including quasi-particle effects and the linear optical response is gained form the solution of the Bethe-Salpeter equation taking excitonic and local-field effects into account. Nonlinear optical coefficients are evaluated on the level of the independent-particle approximation. It is observed that increasing the tantalum amount widens the band gap and nearly linearly affects the optical birefringence. Also some second harmonic generation coefficients vary strongly with the stoichiometry. [ABSTRACT FROM AUTHOR]

This column presents preliminary findings of an intervention to support shared decision making in psychopharmacology consultation. The waiting area in an urban psychiatric medication clinic was transformed into a peer-run Decision Support Center featuring a user-friendly, Internet-based software program with which clients could create a one-page computer-generated report for use in the medication consultation. The Decision Support Center was used 662 times by 189 unique users from a young-adult and general adult case management team from October 2006 to September 2007. All clients had severe mental disorders. Only ten clients refused to use the intervention at some point during the pilot study. Focus groups with medical staff (N=4), clients (N=16), case managers (N=14), and peer-specialist staff (N=3) reported that the intervention helped to create efficiencies in the consultation and empower clients to become more involved in treatment-related decision making. A randomized controlled trial is currently in process. [ABSTRACT FROM AUTHOR]