11,389 research outputs found

    Tuning the Diradical Character and Singlet-Triplet Energy Gap in Diindenoanthracene Derivatives

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    Resumen de la conferenciaOver the last few years we have been utilizing the indenofluorene scaffold1 and, more recently, pi-extended derivatives2 to explore diradical character on a fundamental level. Altering either the center acene core or the outer arene unit results in molecules with varying diradical character values (y) while also changing the singlet-triplet energy gap (EST) of the resultant diradicaloids. Although the literature in recent years has seen a huge increase in the number of new diradicaloids with unique properties, there are very few cases in which modifications are made to the original scaffolds after their initial publication to refine or change the singlet-triplet energy gap or the y index. This is often due to the inherent instability and complex synthesis of such molecules, which makes modification of the original molecule difficult. If the posited applications for organic diradicals are to come to fruition, the ability to incrementally change these properties while maintaining stability will be crucial. To that end computations on a series of modified diindenoanthracene derivatives illustrate the potential to tune these properties incrementally (Figure 1). In the interest of exploring these small changes in y and singlet-triplet gap from an experimental standpoint, the synthesis of these molecules and examination of their chemical, magnetic, and optoelectronic properties will be presented.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    New Interpretation of the 1sigmauplus and 1piu Rydberg States and Valence States of Nitrogen Below the First Ionization Limit

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    Interpretation of Rydberg and valence states of nitrogen below first ionization limi

    Testing of the dwarf galaxy content and the evolutionary status of nearby groups of galaxies

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    We carried out visual and parametric searches for dwarf galaxies in five loose groups of galaxies. Follow-up spectroscopy with the HET has shown a 50% success rate of morphological selection. The evolutionary status of the studied groups differs: while the NGC 6962 group has a partially relaxed core, surrounded by an infall region, the NGC 5005/5033 group and the IC 65 group, which consist only of late-type galaxies, are probably still assembling.Comment: 3 pages, 5 figures, to be published in Astronomische Nachrichten (proceedings of Symposium 6 of the JENAM 2008, Vienna

    What went wrong with: "The Interaction of Neutrons With 7Be: "Lack of Standard Nuclear Physics Solution to the "Primordial 7Li Problem"", by M. Gai [arXiv:1812.09914v1]?

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    We comment here on results of the project aimed at measuring the 7Be(n,x) reactions at SARAF, Israel, in 2016, posted by M. Gai in [arXiv:1812.09914v1] without the knowledge of parts of the collaboration and against the explicit veto of the collaborators and the administration of the Paul Scherrer Institut, Switzerland. We address both the experimental shortcomings and the drawbacks in project conduction. M. Gais preprint is labeled as "on behalf of the SARAF Israel-US-Switzerland Collaboration", the author list is given as a reference to another unpublished contribution (cited as [27]) to the NPA8 conference in June 2017 in Catania). However, M. Gai did never have the right to report on unpublished proprietary data of the entire collaboration, and he was not authorized to act "on behalf of the collaboration". The contribution is declared as "accepted for publication", but in fact was retracted during the refereeing process. After several careful data evaluations, we have to state that the results of these measurements are not trustworthy and neither the given experimental data basis nor the corresponding data analysis can be improved further. Therefore, we requested to retract the posting immediately [arXiv:1904.03023]. We have to emphasize that, in our opinion, arXiv is not the appropriate platform for handling frictions in a collaboration. These problems should have been solved internally before publishing. Unfortunately, with his single-handed posting against the explicit disagreement of parts of the collaboration, M. Gai did not leave another possibility. With the present article, we expressed all our concerns and objections and we consider herewith the public discussion of this issue as closed.Comment: arXiv admin note: This version has been removed by arXiv administrators due to copyright infringemen

    Battered Women, Self-Defense, and the Law

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    A Long-Run, Short-Run and Politico-Economic Analysis of the Welfare Costs of Inflation

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    This paper assesses the long-run and short-run (i.e. along the transition path) welfare implications of permanent changes in inflation in an environment with essential money and perfectly competitive markets. The model delivers a monetary distribution that matches moments of the distribution seen in the US data. Although there is potential for wealth redistribution to deliver welfare gains from inflation, the (total) costs of 10 percent inflation relative to zero is over 7 percent of consumption. While these results suggest a dominating real-balance effect of inflation, a politico-economic analysis concludes that the prevailing (majority rule) inflation rate is above the Friedman Rule.Inflation; Welfare; Transitions; Voting

    Money Holdings, Inflation, and Welfare in a Competitive Market

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    This paper examines an environment where money is essential and agents exchange in perfectly-competitive, Walrasian markets. Agents consume and produce a homogeneous good, but hold money to purchase consumption in the event of a relatively low productivity shock. A Walrasian market delivers a non-degenerate distribution of money holdings across agents and avoids some of the computational difficulties associated with the market and pricing assumptions of bilateral matching and bargaining common to search-theoretic environments. The model is calibrated to long-run US velocity, and the welfare costs of inflation are assessed for variable buyer-seller ratios and persistent states of buying and selling.Monetary Policy, Inflation, Welfare, Walrasian Markets

    Approximate analysis of thermal convection in a crystal-growth cell for Spacelab 3

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    The transient and steady thermal convection in microgravity is described. The approach is applicable to many three dimensional flows in containers of various shapes with various thermal gradients imposed. The method employs known analytical solutions to two dimensional thermal flows in simpler geometries, and does not require recourse to numerical calculations by computer

    Market structure and business cycles: Do nominal rigidities influence the importance of real shocks?

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    This paper investigates the relative importance of shocks to total factor productivity (TFP) versus the marginal efficiency of investment (MEI) in explaining cyclical variations. The literature offers contrasting results: TFP shocks are important in neoclassical environments, while relatively unimportant in neo-Keynesian environments. A model with endogenous capital utilization captures both results depending upon the degree of nominal rigidity. In the model, MEI shocks create a wedge between the nominal returns on bonds and capital. Nominal rigidities activate this wedge and place the relative importance on MEI shocks, while TFP shocks dominate when prices are perfectly flexible.Business Cycle Fluctuations; Nominal Rigidities; Exogenous Shocks
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