Maximum cardinality resonant sets and maximal alternating sets of hexagonal systems

AbstractIt is shown that the Clar number can be arbitrarily larger than the cardinality of a maximal alternating set. In particular, a maximal alternating set of a hexagonal system need not contain a maximum cardinality resonant set, thus disproving a previously stated conjecture. It is known that maximum cardinality resonant sets and maximal alternating sets are canonical, but the proofs of these two theorems are analogous and lengthy. A new conjecture is proposed and it is shown that the validity of the conjecture allows short proofs of the aforementioned two results. The conjecture holds for catacondensed hexagonal systems and for all normal hexagonal systems up to ten hexagons. Also, it is shown that the Fries number can be arbitrarily larger than the Clar number

Automated Discovery of porous molecular materials facilitated by characterization of molecular porosity

Porous materials are critical to many industrial sectors, including petrochemicals, energy and water. Traditional porous polymers and zeolites are currently most widely employed within membranes, as adsorbents for separations and storage, and as heterogeneous catalysts. The emerging advanced porous materials, e.g. extended framework materials and molecular porous materials, can boost performance and energy-efficiency of the current technologies because of the unprecedented level of control of their structure and function. The enormous possibilities for tuning these materials by changing their building blocks mean that, in principle, optimally performing materials for a variety of applications can be systematically designed. However, the process of finding a set of optimal structures for a given application could take decades using the traditional materials development approaches. These is a substantial payoff for developing tools and approaches that can accelerate this process. Among advanced porous materials, porous molecular materials are one of the most recent members though they have already attracted significant interest......Programa de Doctorado en Ciencia e Ingeniería de Materiales por la Universidad Carlos III de MadridPresidente: Germán Ignacio Sastre Navarro.- Secretario: Javier Carrasco Rodríguez.- Vocal: Andreas Mavrantonaki

Probing Structure and Dynamics of Amorphous Ice with Small-Molecule Nanoprobes

Water (H2O) is omnipresent on the surface of the Earth, the atmosphere, in nature, and on various celestial bodies.1 The phase diagram of ice exhibits enormous complexity with a plethora of structures and at least two amorphous ices. 2, 3 One of these, low-density amorphous ice, is the most abundant solid in the Universe. Despite H2O’s significance, a full understanding of its role in physical processes remains elusive.4 H2O is capable of building complex hydrogen-bonded networks, and solvates hydrophobic/hydrophilic species.2 Carbon and H2O often coexist, forming interfaces in highly diverse environments.5, 6 This thesis focuses on the structure of H2O in the hydration shells of hydrophobes, tracking the structure and dynamics of vapour deposited amorphous ice with finely dispersed small-molecule nanoprobes. Detailed insights into the morphology of amorphous solid water (ASW)7 and evidence for the presence of three discernible desorption processes present in macroscopic films of amorphous ice have been demonstrated. They are attributed to gas desorption from open cracks, from the collapse of internal voids, and from matrix-isolated gas induced by the irreversible crystallisation of H2O to stacking disordered ice. 7 Due to adamantane (C10H16) being expelled from the amorphous ice matrix upon heating, a number of important insights were gained – the uncharted regime of small hydrophobes surrounded by a H2O network were detected. Neutron diffraction studies of C10H16/ASW employing structure refinement modelling identified a new type of cage structure, with 28 H2O molecules constructed from distorted five- and six-membered rings, named the 566 4 polyhedron. Beyond this phenomenon, unusual, yet strong orientation correlations of the H2O molecules were detected. Intriguingly, the closest O– H bonds were found to point towards the centre of mass of C10H16 – it is quite striking that such a non-polar solute induces intense orientation correlations in its hydration shells. H2O has been at the forefront of many breakthroughs and will continue to push boundaries, probing the chemistry and physics of ice research. 3 References 1. L. del Rosso, M. Celli, F. Grazzi, M. Catti, T. C. Hansen, A. D. Fortes and L. Ulivi, Nat. Mater., 2020, 19, 663-668. 2. C. G. Salzmann, P. G. Radaelli, B. Slater and J. L. Finney, Phys. Chem. Chem. Phys., 2011, 13, 18468-18480. 3. C. G. Salzmann, J. Chem. Phys., 2019, 150, 060901. Abstract 4 4. T. Loerting, K. Winkel, M. Seidl, M. Bauer, C. Mitterdorfer, P. H. Handle, C. G. Salzmann, E. Mayer, J. L. Finney and D. T. Bowron, Phys. Chem. Chem. Phys., 2011, 13, 8783-8794. 5. M. C. De Sanctis, F. Capaccioni, M. Ciarniello, G. Filacchione, M. Formisano, S. Mottola, A. Raponi, F. Tosi, D. Bockelée-Morvan, S. Erard, C. Leyrat, B. Schmitt, E. Ammannito, G. Arnold, M. A. Barucci, M. Combi, M. T. Capria, P. Cerroni, W. H. Ip, E. Kuehrt, T. B. McCord, E. Palomba, P. Beck, E. Quirico, V. T. The, G. Piccioni, G. Bellucci, M. Fulchignoni, R. Jaumann, K. Stephan, A. Longobardo, V. Mennella, A. Migliorini, J. Benkhoff, J. P. Bibring, A. Blanco, M. Blecka, R. Carlson, U. Carsenty, L. Colangeli, M. Combes, J. Crovisier, P. Drossart, T. Encrenaz, C. Federico, U. Fink, S. Fonti, P. Irwin, Y. Langevin, G. Magni, L. Moroz, V. Orofino, U. Schade, F. Taylor, D. Tiphene, G. P. Tozzi, N. Biver, L. Bonal, J. P. Combe, D. Despan, E. Flamini, S. Fornasier, A. Frigeri, D. Grassi, M. S. Gudipati, F. Mancarella, K. Markus, F. Merlin, R. Orosei, G. Rinaldi, M. Cartacci, A. Cicchetti, S. Giuppi, Y. Hello, F. Henry, S. Jacquinod, J. M. Reess, R. Noschese, R. Politi and G. Peter, Nature, 2015, 525, 500. 6. B. A. Buffett, Annu. Rev. Earth Planet Sci., 2000, 28, 477-507. 7. S. K. Talewar, S. O. Halukeerthi, R. Riedlaicher, J. J. Shephard, A. E. Clout, A. Rosu-Finsen, G. R. Williams, A. Langhoff, D. Johannsmann and C. G. Salzmann, J. Chem. Phys., 2019, 151, 134505

MC 2019 Berlin Microscopy Conference - Abstracts

Das Dokument enthält die Kurzfassungen der Beiträge aller Teilnehmer an der Mikroskopiekonferenz "MC 2019", die vom 01. bis 05.09.2019, in Berlin stattfand

Latin as the Language of Science and Learning

This book approaches its topic from three angles: diachronic semantics, a panorama of science and scientific writing in Latin from antiquity up to the present, and linguistic forays that try to demarcate scientific Latin from other registers and to identify groups of different language use among the authors introduced in the panorama. The transition of science from Greek through Latin to the modern vernaculars is especially emphasised

Latin as the Language of Science and Learning

This book approaches its topic from three angles: diachronic semantics, a panorama of science and scientific writing in Latin from antiquity up to the present, and linguistic forays that try to demarcate scientific Latin from other registers and to identify groups of different language use among the authors introduced in the panorama. The transition of science from Greek through Latin to the modern vernaculars is especially emphasised

Proceedings of the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008

This volume contains full papers presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, between September 4th and 6th, 2008.FC