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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]

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]

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]

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 incorporation process of a defined 13C- and 14C-labeled nonylphenol isomer (4-(3,5-dimethylhept-3-yl)phenol) into soil-derived organo-clay complexes was investigated. Isolated organo-clay complexes were separated into humic subfractions. Noninvasive (13C-CP/MAS NMR) and invasive methods (sequential chemical degradation, pyrolysis) were applied to obtain detailed information about the mode of incorporation, chemical structure, and change of the incorporation character of nonextractable residues in course of incubation. 13C-CP/MAS NMR measurements of humic acids revealed an increasing incorporation of phenolic compounds during the experimental time which was referred to residues of the introduced 13C-labeled NP isomer. Detailed investigations by means of sequential chemical degradation indicated a predominant incorporation of nonextractable NP isomer residues via reversible ester (amide) bonds. In course of time, the amount of releasable compounds decreased, pointing to altering processes which affected the mode of incorporation. BBr3-treatment, RuO4 oxidation, and thermochemolysis released only low portions of nonextractable radioactivity giving evidence of strongly incorporated residues. With the comprehensive application of complementary methods (e.g., humic matter fractionation, 13C-CP/MAS NMR, sequential chemical degradation) it was possible to provide a comparatively detailed insight into the incorporation behavior of the applied NP isomer. [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]

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]

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]

The adsorption of single methanol molecules on the lithium niobate (0001) surface, commonly referred to as Z-cut, is investigated using first-principles calculations. It is found that the binding energy for molecular adsorption on the negative surface (~1 eV) is about twice as large as for the positive surface. This difference is related to different bond strengths rather than electrostatics. Depending on the reaction path, lithium extraction from the negative surface may occur. This leads to an additional energy lowering by a few tenths of an eV. Larger energy gains are realized by dissociative adsorption, which is an activated process, however. [ABSTRACT FROM AUTHOR]

The dielectric function and second-harmonic generation spectrum of ferroelectric LiNbO3 are calculated from first principles. The calculations are based on the electronic structure obtained within density functional theory. The use of the GW approach to account for quasiparticle effects and the subsequent solution of the Bethe?Salpeter equation lead to a dielectric function in excellent agreement with measured data. The second harmonic generation spectrum calculated within the independent (quasi) particle approximation predicts strong nonlinear coefficients for photon energies above about 1.5 eV. The comparison with measured data suggests that the inclusion of self-energy effects in the nonlinear response improves the agreement with experiment. [ABSTRACT FROM AUTHOR]

Calculations based on (occupation constrained) density functional theory using local as well as hybrid functionals to describe the electron-electron exchange and correlation are combined with many-body perturbation theory in order to determine and rationalize the electronic and optical excitation properties of 2-aminopyrimidine-silver(I) based organic semiconductors and their parent molecules. Large quasiparticle shifts and exciton binding energies of about 4 eV are found in the aminopyrimidine molecules. Both the quasiparticle blueshift and the excitonic redshift are reduced upon crystal formation. They cancel each other partially and thus allow for a meaningful description of the molecular and crystal optical response within the independent-particle approximation. We find a surprisingly strong influence of local-field effects as well as resonant-nonresonant coupling terms in the electron-hole Hamiltonian on the optical properties. The calculations reproduce well measured data and allow for identifying chemical trends with respect to the organic building blocks of the crystals. [ABSTRACT FROM AUTHOR]

Organo-clay complexes in soil are a major sink for xenobiotics and, thus, often enhance their persistence dramatically. However, the knowledge on environmental processes of non-extractable residue formation on a short time scale is very restricted. Therefore, this study examined the distribution of 4-(3,5-dimethylhept-3-yl)phenol (NP) and 4-chloro-2-methylphenoxyacetic acid (MCPA) in soil over a short time period of 48 h and in different soil sub-fractions. The overall proportion of organo-clay-associated bound residues was not only abundant but also in the same range for both substances (MCPA: 8%; NP: 11% of applied C-radioactivity). However, a more detailed view revealed two different distribution patterns: a higher proportion of clay-associated NP was accompanied by a lower content of bound residues, whereas a smaller fraction of clay-associated MCPA was characterized by a higher proportion of non-extractable residues. Further on, a selective accumulation of bound residues among clay-associated humic fractions was observed. NP residues were linked predominantly to humic acids, whereas MCPA residues tended to be incorporated more into fulvic acids. It was evident that the overall distribution was influenced primarily by the physico-chemical properties of the contaminants. This study demonstrates in detail a rapid initial incorporation accompanied by a specific distribution into soil sub-fractions for selected xenobiotics in soil and points to a complex interaction of clay-associated organic matter with low molecular weight compounds. [ABSTRACT FROM AUTHOR]

The quasiparticle band structures and fundamental energy gaps of the rock-salt (rs), zinc-blende (zb), and wurtzite (wz) polymorphs of CaO and AlN are calculated within the G0W0 approximation on top of a self-consistent solution of the generalized Kohn-Sham equation with the hybrid functional HSE03. Based on these reliable electronic structures, the dielectric functions of rs-CaO, zb-AlN, and wz-AlN including excitonic effects are obtained from the solution of the Bethe-Salpeter equation. The peaks and structures in the absorption spectra are analyzed in terms of critical points in the joint band structure and the joint density of states. We find that some features of the optical absorption can be clearly assigned to bound excitonic states located at M0 or M1 critical points, while others are merely due to a large joint density of states. [ABSTRACT FROM AUTHOR]

Anthropogenic contaminants like nonylphenols (NP) are added to soil, for instance if sewage-sludge is used as fertilizer in agriculture. A commercial mixture of NP consists of more than 20 isomers. For our study, we used one of the predominate isomers of NP mixtures, 4-(3,5-dimethylhept-3-yl)phenol, as a representative compound. The aim was to investigate the fate and distribution of the isomer within soil and soil derived organo-clay complexes. Therefore, 14C- and 13C-labeled NP was added to soil samples and incubated up to 180 days. Mineralization was measured and soil samples were fractionated into sand, silt and clay; the clay fraction was further separated in humic acids, fulvic acids and humin. The organo-clay complexes pre-incubated for 90 or 180 days were re-incubated with fresh soil for 180 days, to study the potential of re-mobilization of incorporated residues. The predominate incorporation sites of the nonylphenol isomer in soil were the organo-clay complexes. After 180 days of incubation, 22 % of the applied 14C was mineralized. The bioavailable, water extractable portion was low (9 % of applied 14C) and remained constant during the entire incubation period, which could be explained by an incorporation/release equilibrium. Separation of organo-clay complexes, after extraction with solvents to release weakly incorporated, bioaccessible portions, showed that non-extractable residues (NER) were preferentially located in the humic acid fraction, which was regarded as an effect of the chemical composition of this fraction. Generally, 27 % of applied 14C was incorporated into organo-clay complexes as NER, whereas 9 % of applied 14C was bioaccessible after 180 days of incubation. The re-mobilization experiments showed on the one hand, a decrease of the bioavailability of the nonylphenol residues due to stronger incorporation, when the pre-incubation period was increased from 90 to 180 days. On the other hand, a shift of these residues from the clay fraction to other soil fractions was observed, implying a dynamic behavior of incorporated residues, which may result in bioaccessibility of the NER of nonylphenol. [ABSTRACT FROM AUTHOR]

Environmental processes can affect the stereochemical properties of organic pollutants. In particular, biotic processes like microbial transformations or membrane penetration alter the ratios of enantiomers as well as diastereomers. These effects have been intensively used not only in environmental studies but also in medicine, toxicology, pharmacy, and agricultural sciences. However, in order to identify unambiguously biotic-initiated alteration of organic compounds, the knowledge on the stereoselective effect of all relevant processes is mandatory. Therefore, here we report the first evidence for a stereospecific formation of non-extractable residues of a xeniobiotic in a highly relevant soil subfraction, the organo-clay complexes. In this study, soils were spiked with labeled and unlabeled nonylphenol isomer, and incubation experiments were performed to study its long-term incorporation behavior into soil-derived organo-clay complexes under abiotic and biotic conditions. Besides the extractable particle-associated proportion especially the humic fractions comprising the bound residues have been analyzed by GC/MS. Our results from biotic experiments revealed alterations of the diastereomeric composition of the contaminant in the different soil humic subfractions. A depletion of the first eluting diastereomer as expressed by diastereomeric ratios around 0.6 has been observed for the extractable fraction, whereas the non-extractable proportion was enriched in the first diastereomer (diasteremoric ratio around 1.0). On the contrary, the diastereomeric ratios remained unaffected during the abiotic experiments (diasteremoric ratio around 0.8). These systematic observations give clear evidence that the process of microbial-assisted incorporation of nonylphenol into soil organo-clay complexes is a stereoselective process. To our knowledge, this is the first report on a stereoselective incorporation process of organic substances forming non-extractable residues. Consequently, the formation of non-extractable residues has to be considered in environmental studies dealing with stereoselective analysis of organic pollutants in soils to study their microbial transformation. [ABSTRACT FROM AUTHOR]

Research is mixed as to whether self-generation improves memory for the source of information. We propose the hypothesis that positive generation effects (better source memory for self-generated information) occur in reality-monitoring paradigms, while negative generation effects (better source memory for externally presented information) tend to occur in external source-monitoring paradigms. This hypothesis was tested in an experiment in which participants read or generated words, followed by a memory test for the source of each word (read or generated) and the word's colour. Meiser and Bröder's (2002) multinomial model for crossed source dimensions was used to analyse the data, showing that source memory for generation (reality monitoring) was superior for the generated words, while source memory for word colour (external source monitoring) was superior for the read words. The model also revealed the influence of strong response biases in the data, demonstrating the usefulness of formal modelling when examining generation effects in source monitoring. [ABSTRACT FROM AUTHOR]

This article demonstrates how multinomial processing tree models can be used as assessment tools to measure cognitive deficits in clinical populations. This is illustrated with a model developed by W. H. Batchelder and D. M. Riefer (1980) that separately measures storage and retrieval processes in memory. The validity of the model is tested in 2 experiments, which show that presentation rate affects the storage of items (Experiment 1) and part-list cuing hurts item retrieval (Experiment 2). Experiments 3 and 4 examine 2 clinical populations: schizophrenics and alcoholics with organic brain damage. The model reveals that each group exhibits deficits in storage and retrieval, with the retrieval deficits being stronger and occurring more consistently over trials. Also, the alcoholics with organic brain damage show no improvement in retrieval over trials, although their storage improves at the same rate as a control group. [ABSTRACT FROM AUTHOR]

Compares the effectiveness of auditory and visual stimuli in eliciting the tip-of-the-tongue phenomenon in California. Description of the tip-of-the-tongue phenomenon; Use of semantic stimuli in eliciting responses; Factors affecting responses to auditory stimuli.

Examines whether auditory stimuli could elicit the tip-of-the-tongue state. Presentation of segments of 50 television theme songs to participants; Comparison between men and women in terms of tip-of-the-tongue experiences.

Analyzes multinomial model's insight into the recognition-failure paradigm. Focus on previous theories and experiments; Research on the recognition-failure paradigm; Validity of multinomial model and other models; More details; Conclusion.

Replies to the article `Comments on Batchelder and Riefer's Multinomial Model for Source Monitoring,' by R.A. Kinchla in the January 1994 issue of `Psychological Review'. Presentation of the considerations that led to the multinomial model for source monitoring; Specific concerns with Kinchla's critique; Arguments in favor of the model; Comments on statistical decision theory.

Presents a family of processing models for the source-monitoring paradigm in human memory. Source monitoring is used to assess memory deficits in various subject populations; Shows that sometimes multinomial models support and augment the authors' original analyses with ad hoc statistical measures but at other times, analyses show dramatic revision. Data representation.

To investigate films of metal clusters, a neutral lead cluster beam, generated by inert gas aggregation, is characterized via time-of-flight mass spectroscopy and subsequently used for growing a thin film ( d=100 Å) on a cold sapphire substrate. In an annealing program the temperature dependence of the electrical resistance of the film is determined by the dc 4-probe technique. Directly after deposition a superconducting transition at T=5.6 K is observed which is shifted to higher temperatures with increasing annealing temperature ( T=6.5 K after annealing at room temperature). [ABSTRACT FROM AUTHOR]

The influence of excitonic and local-field effects on the second-harmonic-generation spectrum of zinc-blende ZnS, ZnSe, and ZnTe is studied from first principles using the Bethe-Salpeter equation. The calculations are based on the theory of R. Leitsmann et al. [Phys. Rev. B 71, 195209 (2005)], which we extended to the low-frequency range. The dielectric function and the second-harmonic-generation spectrum have been obtained within the independent (quasi)particle approximation and within the Bethe-Salpeter approach. The calculations demonstrate that the linear and the nonlinear optical properties are similarly affected by excitonic and local-field effects. The computed spectra are furthermore compared with measurements and calculations within the time-dependent density-polarization functional theory (TD-DPFT) in the real-time framework. The present approach most commonly suggests stronger excitonic effects than observed in the real-time TD-DPFT calculations, while local-field corrections are comparably described. Although agreement is found between the Bethe-Salpeter spectra and measurements for the dielectric function, deviations from the experimental data are observed for second-harmonic generation. [ABSTRACT FROM AUTHOR]

Presents information on palm Lisa, a cultivar of Sabal palmetto found in Florida. Use of Sabal palmetto in landscaping; Characteristics of the palm; Description of its leaves.

OnTrackNY provides early intervention services to young people with early psychosis throughout New York State. This report describes the impact of the COVID-19 pandemic on community participation of OnTrackNY program participants and their families. Thirteen participants and nine family members participated in five focus groups and three individual semi-structured interviews. Data were analyzed using a summary template and matrix analysis approach. Major themes highlight the negative impacts of the pandemic with reports of decreased socializing or using online means to connect, unemployment, challenges with online learning and a decrease in civic engagement. Positive impacts include more time to deepen connections with family and valued friendships and engage in activities that promote wellness and goal attainment. Implications for coordinated specialty care programs include adapting services to promote mainstream community integration and creating new strategies for community involvement of young people within a new context brought forth by the pandemic. [ABSTRACT FROM AUTHOR]

The influence of electronic many-body interactions, spin-orbit coupling, and thermal lattice vibrations on the electronic structure of lithium niobate is calculated from first principles. Self-energy calculations in the GW approximation show that the inclusion of self-consistency in the Green function G and the screened Coulomb potential W opens the band gap far stronger than found in previous G0W0 calculations but slightly overestimates its actual value due to the neglect of excitonic effects in W. A realistic frozen-lattice band gap of about 5.9 eV is obtained by combining hybrid density functional theory with the QSGW0 scheme. The renormalization of the band gap due to electron-phonon coupling, derived here using molecular dynamics as well as density functional perturbation theory, reduces this value by about 0.5 eV at room temperature. Spin-orbit coupling does not noticeably modify the fundamental gap but gives rise to a Rashba-like spin texture in the conduction band. [ABSTRACT FROM AUTHOR]

A correction to the article "First evidence for a stereoselective incorporation of nonylphenol diastereomers in solid-derived organo-clay complexes" that is published in this issue is presented.

Looks at what the author's son told her about her granddaughter's visit to a bookshop during the author's weekly conversation between her son. Name of author's granddaughter; Name of book granddaughter selected; Dialogue which took place between granddaughter and clerk.

Neutral binary clusters of Pb-As, Pb-Se, Pb-Te, Bi-In and Bi-Te are generated by inert gas condensation in a double oven source and probed by electron impact. Cluster ions corresponding to the Zintl polyanions Pb and Pb with respect to atom and valence electron number, are strongly enriched by electron induced dissociation ((PbAs), (BiIn), (PbAs), (BiIn)). For the corresponding systems, no other compound cluster ions are enriched in a comparable manner. Enhanced stability is found for (PbAs) ( n=7, 10, 13) and (BiTe), which are isoelectronic with neutral 'magic' Pb clusters and the very stable Bi molecule, respectively. [ABSTRACT FROM AUTHOR]

Compound cluster ions of heavy post-transition atoms (In, Pb, As, Sb, Bi) are enriched by electron induced dissociation if they are analogous to the Zintl polyanions Pb and Pb with respect to the atom and valence electron number. [ABSTRACT FROM AUTHOR]