Quantum-mechanical calculations of the stabilities of fluxional isomers of C_4H_7^+ in solution

Although numerous quantum calculations have been made over the years of the stabilities of the fluxional isomers of C4H7+, none have been reported for other than the gas phase (which is unrealistic for these ionic species) that exhibit exceptional fluxional properties in solution. To be sure, quantum-mechanical calculations for solutions are subject to substantial uncertainties, but nonetheless it is important to see whether the trends seen for the gas-phase C4H7+ species are also found in calculations for polar solutions. Of the C4H7+ species, commonly designated bisected-cyclopropylcarbinyl 1, unsym-bicyclobutonium-2, sym-bicyclobutonium 3, allylcarbinyl 4, and pyramidal structure 6, the most advanced gas-phase calculations available thus far suggest that the order of stability is 1 ≥ 2 ≥ 3 >> 4 >> 6 with barriers of only ~1 kcal/mol for interconversions among 1, 2, and 3. We report here that, when account is taken of solvation, 2 turns out to be slightly more stable than 1 or 3 in polar solvents. The pattern of the overall results is unexpected, in that despite substantial differences in structures and charge distributions between the primary players in the C4H7+ equilibria and the large differences in solvation energies calculated for the solvents considered, the differential solvent effects from species to species are rather small

Raman spectroscopy as a versatile tool to study organic biradicals

Since -conjugated organic molecules were probed as potential semiconducting materials, suitable for replacing the widely used silicon technologies, their structural, optical and conductive properties have been under study to improve their application in organic electronics and to make possible their ad hoc synthesis. In this sense, the modification of the -electron delocalization path is one of the available tools to tune the properties of the molecules to obtain the desired characteristics for the fabrication of these devices. One of the parameters employed to tailor -conjugated organic molecules for organic electronics is the diradical character. A progressive change in the diradical contribution to the ground electronic state structure can tune some of the main system features, highlighting the HOMO-LUMO energy gap and the aggregation mode. The main drawback of this approach is the loss of chemical stability when increasing the diradical character of these molecules. On the other hand, the -electron delocalization can be interrupted introducing a perpendicularly conjugated path. The competition of these two cross-conjugated patterns leads to a new 2-dimensional delocalization scenario that changes the electronic properties of the studied materials. In this project, we present a stable quinoidal quaterthiophene diradical that possess outstanding stability and conductivity properties. [1] The combination of the diradical character together with the possibility to delocalize the electron density through two different perpendicular paths explain its exceptional behavior in comparison with the other members of the series, or with its linearly conjugated analogues. The balance between these two properties has been evaluated through UV-Vis-NIR electronic spectroscopy and Raman and IR vibrational spectroscopy in the neutral and charged forms of the target molecule and similar non-cross-conjugated samples.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Corrections on repeating ground-track orbits and their applications in satellite constellation design

The aim of the constellation design model shown in this paper is to generate constellations whose satellites share the same ground-track in a given time, making all the satellites pass over the same points of the Earth surface. The model takes into account a series of orbital perturbations such as the gravitational potential of the Earth, the atmospheric drag, the Sun and the Moon as disturbing third bodies or the solar radiation pressure. It also includes a new numerical method that improves the repeating ground-track property of any given satellite subjected to these perturbations. Moreover, the whole model allows to design constellations with multiple tracks that can be distributed in a minimum number of inertial orbits

A Note on Supercyclic Operators in Locally Convex Spaces

[EN] We treat some questions related to supercyclicity of continuous linear operators when acting in locally convex spaces. We extend results of Ansari and Bourdon and consider doubly power bounded operators in this general setting. Some examples are given.We are indebted to Prof. Jose Bonet for his helpful suggestions on the topic of this paper. The authors were partially supported by the project MTM2016-76647-P.Albanese, AA.; Jornet Casanova, D. (2019). A Note on Supercyclic Operators in Locally Convex Spaces. Mediterranean Journal of Mathematics. 16(5):1-10. https://doi.org/10.1007/s00009-019-1386-yS11016

Dissipative operators and additive perturbations in locally convex spaces

"This is the peer reviewed version of the following article: Albanese, Angela A., and David Jornet. 2015. Dissipative Operators and Additive Perturbations in Locally Convex Spaces. Mathematische Nachrichten 289 (8 9). Wiley: 920 49. doi:10.1002/mana.201500150, which has been published in final form at https://doi.org/10.1002/mana.201500150. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] Let (A, D(A)) be a densely defined operator on a Banach space X. Characterizations of when (A, D(A)) generates a C-0-semigroup on X are known. The famous result of Lumer and Phillips states that it is so if and only if (A, D(A)) is dissipative and rg(lambda I - A) subset of X is dense in X for some lambda > 0. There exists also a rich amount of Banach space results concerning perturbations of dissipative operators. In a recent paper Tyran-Kaminska provides perturbation criteria of dissipative operators in terms of ergodic properties. These results, and others, are shown to remain valid in the setting of general non-normable locally convex spaces. Applications of the results to concrete examples of operators on function spaces are also presented. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimThe research of the second author was partially supported by MINECO of Spain, Project MTM2013-43540-P, by Programa de Apoyo a la Investigacion y Desarrollo de la UPV, PAID-06-12 and by Generalitat Valenciana ACOMP/2015/186.Albanese, AA.; Jornet Casanova, D. (2016). Dissipative operators and additive perturbations in locally convex spaces. Mathematische Nachrichten. 289(8-9):920-949. https://doi.org/10.1002/mana.201500150S9209492898-9Albanese, A. A., Bonet, J., & Ricker, W. J. (2010). C0-semigroups and mean ergodic operators in a class of Fréchet spaces. Journal of Mathematical Analysis and Applications, 365(1), 142-157. doi:10.1016/j.jmaa.2009.10.014Albanese, A. A., Bonet, J., & Ricker, W. J. (2011). Mean ergodic semigroups of operators. Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales. Serie A. Matematicas, 106(2), 299-319. doi:10.1007/s13398-011-0054-2Albanese, A. A., Bonet, J., & Ricker, W. J. (2013). Montel resolvents and uniformly mean ergodic semigroups of linear operators. Quaestiones Mathematicae, 36(2), 253-290. doi:10.2989/16073606.2013.779978Albanese, A. A., Bonet, J., & Ricker, W. J. (2013). Convergence of arithmetic means of operators in Fréchet spaces. Journal of Mathematical Analysis and Applications, 401(1), 160-173. doi:10.1016/j.jmaa.2012.11.060Albanese, A. A., Bonet, J., & Ricker, W. J. (2014). Uniform mean ergodicity of $C_0$-semigroups\newline in a class of Fréchet spaces. Functiones et Approximatio Commentarii Mathematici, 50(2), 307-349. doi:10.7169/facm/2014.50.2.8Domański, P., & Langenbruch, M. (2011). On the abstract Cauchy problem for operators in locally convex spaces. Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales. Serie A. Matematicas, 106(2), 247-273. doi:10.1007/s13398-011-0052-4Frerick, L., Jordá, E., Kalmes, T., & Wengenroth, J. (2014). Strongly continuous semigroups on some Fréchet spaces. Journal of Mathematical Analysis and Applications, 412(1), 121-124. doi:10.1016/j.jmaa.2013.10.053B. Jacob S.-A. Wegner Asymptotics of solution equations beyond Banach spaces Semigroup ForumJacob, B., Wegner, S.-A., & Wintermayr, J. (2015). Desch-Schappacher perturbation of one-parameter semigroups on locally convex spaces. Mathematische Nachrichten, 288(8-9), 925-934. doi:10.1002/mana.201400116Köthe, G. (1983). Topological Vector Spaces I. Grundlehren der mathematischen Wissenschaften. doi:10.1007/978-3-642-64988-2Köthe, G. (1979). Topological Vector Spaces II. Grundlehren der mathematischen Wissenschaften. doi:10.1007/978-1-4684-9409-9KOMATSU, H. (1964). Semi-groups of operators in locally convex spaces. Journal of the Mathematical Society of Japan, 16(3), 230-262. doi:10.2969/jmsj/01630230Kōmura, T. (1968). Semigroups of operators in locally convex spaces. Journal of Functional Analysis, 2(3), 258-296. doi:10.1016/0022-1236(68)90008-6Lumer, G., & Phillips, R. S. (1961). Dissipative operators in a Banach space. Pacific Journal of Mathematics, 11(2), 679-698. doi:10.2140/pjm.1961.11.679Miyadera, I. (1959). Semi-groups of operators in Fréchet space amd applications to partial differential equations. Tohoku Mathematical Journal, 11(2), 162-183. doi:10.2748/tmj/1178244580Moscatelli, V. B. (1980). Fréchet Spaces without continuous Norms and without Bases. Bulletin of the London Mathematical Society, 12(1), 63-66. doi:10.1112/blms/12.1.63Tyran-Kamińska, M. (2009). Ergodic theorems and perturbations of contraction semigroups. Studia Mathematica, 195(2), 147-155. doi:10.4064/sm195-2-4S.-A. Wegner The growth bound for strongly continuous semigroups on Fréchet spaces Proc. Edinb. Math. Soc. (2) (to appear) 10.1017/S001309151500031

2D Necklace Flower Constellations

The 2D Necklace Flower Constellation theory is a new design framework based on the 2D Lattice Flower Constellations that allows to expand the possibilities of design while maintaining the number of satellites in the configuration. The methodology presented is a generalization of the 2D Lattice design, where the concept of necklace is introduced in the formulation. This allows to assess the problem of building a constellation in orbit, or the study of the reconfiguration possibilities in a constellation. Moreover, this work includes three counting theorems that allow to know beforehand the number of possible configurations that the theory can provide. This new formulation is especially suited for design and optimization techniques

Successful Treatment of Acute Prostatitis Caused by Multidrug-Resistant Escherichia coli With Tigecycline Monotherapy

We present a successful treatment, with tigecycline monotherapy, of acute prostatitis caused by multidrug-resistant Escherichia coli harboring an NDM-1 carbapemenase along with a CMY-2 cephalosporinase and a TEM ESBL