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Advances in Quantum Chemistry : Volume 66
- 2013
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- In this issue of the Advances in Quantum Chemistry, Volume 66, the readers are offered an interesting mix of themes, first an account of the high-Tc mechanism of a recently discovered class of superconductors, with a characteristic alternant lattice structure; a lucid treatise of some of the fundamental core concepts, labeled as conundrums in chemical physics, a state-of-the art description of the electron-dynamics, END, method; and finally new developments regarding unified descriptions of embeddings in both a discrete and a continuum polarizable environment within multiconfigurational self-consistent field (MCSCF) theories. In Chapter 1, the authors review a contemporary hot topic, that is, theories concerning the understanding of a newly discovered class of high-Tc superconductors, that is, the iron-based pnictides and the chalcogenic compounds exhibiting, in analogy with the cuprates previously discovered and discussed, a characteristic alternant lattice structure. Since recent speculations suggest the emergence of superconductivity from repulsive electronic correlations, the authors demonstrate in this review a detailed mechanism for this class of condensates originating in the alternant structure as well as simultaneously exhibiting Yang’s celebrated concept of off-diagonal long-range order, ODLRO. In addition, it is pointed out that the authors proposed conformational stabilization with strong interactions as a possible mechanism for high-temperature superconductivity more than 30 years ago and that a similar repulsive coulomb mechanism for the alternant lattice structure is central to the occurrence of the most stable condensates, exhibiting dx2-y2symmetry for the cuprates and sign alternating s-wave or s±condensate symmetries for the pnictides. In Chapter 2, several fundamental concepts and models that appear challenging to students and teachers in chemistry interrelated scientific disciplines have been presented under the title “Conundrums in Chemical Physics.” In particular, the author provides explanations and validations of concepts such as those of the classical Marcus model and the quantum mechanical Landau theory of electron transfer reactions, or further the semi-classical Landau–Zener approach for diabatic transitions, integrated by the notion of reaction paths as well as the progression of stochastic models, etc. In addition, fundamental mathematical approaches, like the Langevin-, the Fokker–Planck-, and the Klein–Kramers’ equation, are illustrated and evolved. Possible objections of the work presented here concern the connection between Kramers’ account of Transition State theory in the context of phase space diffusion and the irreversible version of the Liouville equation. By transferring the classical concepts to the field of Quantum Chemistry, the author meets the complaints and outlines a time-dependent Liouville superoperator space and Trace Algebra with an emphasis to facilitate the description of the issues facing the developmentof a modern quantum mechanical theory of irreversible processes in analogy with their classical counterparts. Chapter 3 concerns a method for treating molecular dynamics in a nonadiabatic way that treats electrons and nuclei simultaneously. The method, electron nuclear dynamics or END, as presently implemented, reduces the nuclear wavefunction to zero width, making the nuclei act classically, while maintaining Thouless single-determinantal description of the electrons. Typically, the method is implemented in its simplest form and thus has some application problems, as described in this chapter. The chapter deals with the computational simplification of the problem by introducing a density functional (DFT)-based treatment of the electronics in order to include some correlation and yet maintain a single-determinantal description. Chapter 4 in this volume deals with the linear response properties of an electronic state of a system embedded in a polarizable medium. The treatmentis based on an MCSCF theory and leads to the description of the electronic state of an embedded molecule.The content of this volume is quite diverse, and it is hoped that the volume will provide an interesting read for all who have interest in the quantum mechanical description of a wide variety of molecular systems.
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Advances in Quantum Chemistry : Quantum Boundaries of Life
- 2020
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- The boundaries between organic and live matter are sites of the most significant interactions and transformations in science from biology through chemistry and physics. In this volume, we are happy to present our readers with a unique thematic volume 82 of the Advances in Quantum Chemistry devoted to the theme Quantum Boundaries of Life. We present a transdisciplinary exploration of the quantum boundaries relating to a molecular basis of life and consciousness, where the integration process begins at the molecular level, grounded on the research agenda, concepts, and shared values of quantum chemistry. There is a boundary to the integration process, but it provides the reality of a deeper foundation that is the quintessential mechanism of life where reality isomorphically aligns with consciousness.The evolutionary biologist Ernst Mayr contended three principal classes of scientific reduction in biology, i.e., the ontological, the epistemological, and the methodological. Molecular catalysis is central in molecular evolution, like all other teleological phenomena, advanced by Darwin's theory of evolution. Hence, it follows that molecular reductionism provides the ground level for the most straightforward kind of life, based on the evolution of the prokaryotic to the more complex eukaryotic cell, where the wire-like flow of charges, protons, ions, and other molecular constituents of the microenvironment, including elements of the cytoskeleton, extends to the cellular membrane itself representing the quantum machinery of life and consciousness. However, as all quantum physicists know, the reading of “Pioneering Quantum Mechanics” contains, among all versions, the von Neumann-Wigner interpretation “consciousness causes collapse of the wave function.” Irrespective of the copiousness of these views, the reduction argument spirals back to fundamental biological concepts within the life sciences.The present volume editors represent the fields of biological applications of quantum chemistry in the broadest sense. First, it is important to recognize the subtle difference between quantum physics and quantum chemistry. The former is strictly reductionistic, using quantum mechanics and field theory to hierarchically formulate the fundamental subsystems of nature, whereas the latter attempts to use the “quantum platform” to build more complex systems while setting fundamental goals for the discipline. Second, to take the step from quantum chemistry to quantum biology, one must permeate a crucial barrier, namely how to account for functionality. This functional interaction is nonlocal and across scale as opposed to the classical concept of levels, which is a continuous notion. So, microscale, mesoscale, and macroscale assume level continuity—a kind of biological nonlocality. Third, we have two types of demarcations: (1) the quantum boundaries of life, e.g., when quantum chemistry becomes quantum biology and (2) the often-discussed quantum-classical interface. The quantum-classical boundary has, for a long time, been the concern of theoretical physics and will only indirectly be connected with the quantum boundary of life. Physicists suggest that the quantum-classical transition should be linked with John Wheeler's quantum foam or spacetime fluctuations. At the same time, chemically oriented scientists believe that the interface hides in the process of decoherence, and hence the quantum boundary of life must be of thermoquantal origin, derived from the entropy-temperature duality.How do we go about this boundary, this demarcation sector or frontier zone? What will we find? Life should, first of all, always be inside such a boundary—or as is suggested in the final contribution that it is more relevant to view Life as a quantum phenomenon intrinsic to Nature—such as all biological organisms that have acquired an intrinsic function. Teleological notions in biology adumbrate that living organisms have intrinsic purposes that begin with simple physical interactions between entities of what we denote as nonliving matter evolving into more complex correlative communicative exchanges of anticipation and information. What are the physical attributes of such intrinsicality? One should remember that the mechanisms of teleological causation are “hidden”; we fail to perceive reality as a conjugate link between matter and experience. As mathematicians, biologists, and chemists, including ourselves, scientists seek to discover the isomorphic connection between matter, life, and consciousness.Several fundamental stumbling blocks need to be unraveled. The most striking one is how to handle the threat of decoherence, destroying molecular wave interferences due to incoherent scattering between atomic, ionic, and molecular constituents, ubiquitous aqueous solutions, etc. in the wet and hot environment of a human brain. The thermal noise, about 0.025 eV at 310 K, might wash away subtle quantum effects making the latter seemingly obsolete. In other words, quantum decoherence becomes an unavoidable obstacle in the organization of energy to maintain order and overcoming entropy production in living systems. Another difficulty relates to the notion of energy-time scales, conjugated through the uncertainty principle, with the consequence that integrated information, as a synergy of emerging information, becomes impossible. This is so due to the irreducible character of the degenerate physical representation that derives from the law of self-reference suggesting a holistic view, i.e., an informational holarchy, which to some extent reminds of Arthur Koestler's intemperate critique of the classical citadel of orthodoxy culminating in his contentious notion of holons. Accordingly, our present conception is founded on an interrelation-informational structure, where the whole is nonsynergistically affected by nonintegrated information. This relationalism provides the key to understanding how nonintegrated information holistically subsumes concrescence while conferring negentropic information as a transformation process of quantum nature.As a consequence of the above, temperature dependencies must be addressed in a serious quantum-theoretical formulation of life processes that should concern systems evolving far from equilibrium, with the latter dissipating energy and entropy to the environment. Our warm brain is an example of this, suggesting that neural processes are thermal and, therefore, claimed to be nonquantum. However, there is a disparity between bound quantum states and quantum effects associated with the continuum and rigorous extensions to open system quantum dynamics. The chapters will deal with various situations and circumstances related to quantum theory in the broadest sense, such as tunneling and resonance formation, including density matrices and associated generalizations.Assuming that animate and inanimate systems are subject to the same physical principles, one might wonder what sets them apart at the quantum boundary? To answer this question, one cannot avoid appealing to a teleological notion of function, which, according to Jacques Monod, constitutes “a profound epistemological contradiction” effectively exhibiting a central problem in biology. We are left with the question of etiology, and it is here where the quantum boundaries of life are espoused. The formulation must also include the macroscopic scale to encompass the teleological functions from quantum chemistry to quantum biology. However, as ventilated above, quantum effects, asserted to be essential for life processes, cannot survive as eigenfunctions to the Schrödinger equation, i.e., will not be coherent in the thermal medium, since its wave properties cannot resist decoherence by thermal perturbations. The density matrix provides a more general representation of the state of a quantum system, reflecting upon its nonlocality, impending localization, like classical particles in a biological medium, such as the microstructure of neurons.Although modern quantum chemistry goals are to accumulate chemical data from, e.g., the physical constants and atomic numbers employing the Schrödinger equation and its Liouville generalizations, its base is quantum physics, for instance, treating momentum-space and energy-time as fundamental conjugate variables-operators. Imbricating chemical physics adds fundamental technological capabilities facing the atomic and molecular levels that will restrict the concept of a quantum boundary of life toward quantum delocalization and long-range correlative information. In what follows, the invited authors have examined various problems related to their expertise in the stride to uncover the gap between the function of the cells, such as neurons, in a living organism—the easy problem—and the conscious experience, how it is like to be—the hard problem. Cognitivism mistakes consciousness for mindless neural network computations. As is the case with naive realism, i.e., with its primary focus on visual perception and a total lack of a self-referential basis, it does not work when dealing with the hard problem of consciousness.The first chapter complements this Preface, answering the question already posed by Erwin Schrödinger, “What is Life?” The conclusion is that life is a quantum phenomenon to be further explicated in what follows. The next contribution presents an interesting confronting view that pioneering quantum mechanics is incapable of formulating emotive mental states (feelings). While admitting that quantum mechanical concepts may have different meanings for each discipline, the authors review several unsolvable problems for the consideration of transcendental mental states rationalizing cognitive abilities such as memory. In response, they develop a tripartite neural mechanism with molecular underpinnings, fusing psychology with biochemistry. An appealing conclusion is a suggestion that the encod
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Advances in Quantum Chemistry Vol. 77
- 2018. - 77
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- With this preface we are happy to present volume 77 of the Advances in Quantum Chemistry to our readers. In the present volume we portray a varied set of dishes of scientific accomplishments, which we hope will be both stimulating and provoke discussion. The tray begins with general topics in Life Sciences and Medicine, and continues with fundamental applications of Aromatic Maps, followed by considering more exact treatments of quantum systems, like accurate few particle calculations, determinations of relativistic ionization cross sections, and then via quantum control of optical frequency combs to the admittance of endohedral confinement, non-Hermitian descriptions of electron-molecule resonances and finally in the development of spheroidal coordinates for Coulomb Sturmians for the speed-up of molecular calculations.The introductory article concerns an added celebration of the scientific leadership of Per-Olov Löwdin, see the AQC Löwdin Memorial Volume, issue 74 for original contributions. The author, a student “getting lost” in the research organizations of high-tech world-wide industries like Sandvik AB, and IBM, did not abandon the field as he later joined the IBM Almaden Research in San Jose as their Director of Quantum Chemistry. Through his lead involvement in the IBM-Roche collaboration he developed growing concerns regarding Life Sciences and Medicine, which upon retirement encouraged him to found his own company, while writing a highly praised book on nano-technology.The second chapter continues the Life Science theme with a fundamental delving into the topic of the origin of life. Using quantum entanglement algorithms for duplex RNA genome systems, interesting replacement repair enzymes outline entanglement-enabled bases for e.g. age-related disorders, like Huntington’s-, Alzheimers’ decease etc.After these two chapters there follows an up-to-date and detailed review of electron-atom collision processes, including relativistic effects, with particular theoretical considerations to electron impact on inner-shell ionization cross sections of neutral atoms with atomic numbers matching appropriate L, M, shells and subshells.In chapter 4, the father of the connectivity index in chemical graph theory, reviews the structural approach of aromaticity, from the well-known concepts of Kekulé (valence structures), Pauling (bond orders) and Clar (aromatic sextet) to modern characterizations of local and global aromaticities.The authors of the ensuing chapter advance an accurate method for the description of the stability of three-particle systems, by treating all the particles on an equal footing exploring the effects of nuclear motion and electron correlation in few-body systems.Chapter 6 discusses some aspects of excitation in ultracold systems. The authors describe a system they have developed to achieve adiabatic excitations, which is a step towards experimental realization.In chapter 7, the authors study endohedral cavity effects of hydrogen dipole oscillator strength sum rules Sk and Ik, showing that they are strongly affected by the confinement strength with potential implications in material science.The theoretical background for the treatment of atom/molecule resonances using complex scaled multi-configurational methods is developed in chapter 8, and reviewed in some detail. Novel applications to low-energy electron-atom/molecules scattering resonances are presented and compared with other methods and experiment.In the final chapter Coulomb Sturmian functions, defined in spheroidal coordinates, are shown to substantially speed the convergence for molecular calculations, while exhibiting the characteristic feature of preferred bond directions around an atom in contrast to utilizing the customary Coulomb spherical basis. As presented above, volume 77 prepares a large dish that contains an assorted mix of courses, involving both fundamental theory and state-of-the-art applications. The contributing authors have fostered great efforts to share their knowledge and visions. As series editors, we hope that the present volume will transmit the same delight and satisfaction as we, and also the contributors, did exhibit during the preparation of this volume. John R. SabinErkki J. Brändas
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Advances in Quantum Chemistry. vol 81 : Chemical Physics and Quantum Chemistry
- 2020
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- This volume collects 11 selected papers from the scientific contributions presented at the 10th Congress of the International Society for Theoretical Chemical Physics (ISTCP-X), organized by a team led by Professor Kenneth Ruud at the University of Tromsø—The Arctic University of Norway, from July 11 to 17, 2019. The ISTCP-X Congress in Tromsø followed the format established at the nine previous meetings:ISTCP-I: Professor Ramon Carbo-Dorca, Girona (Spain), June 28–July 3, 1993ISTCP-II: Professor Sean P. McGlynn, New Orleans (LA, USA), April 9–13, 1996ISTCP-III: Professor Miguel Castro, Mexico City (DF, Mexico), November 8–13, 1999ISTCP-IV: Professor Jean Maruani, Marly-le-Roi (Paris, France), July 9–16, 2002ISTCP-V: Professor Peter Politzer, New Orleans (LA, USA), July 20–26, 2005ISTCP-VI: Professor Yan Alexander Wang, Vancouver (BC, Canada), July 19–24, 2008ISTCP-VII: Professor Hiromi Nakai, Waseda (Tokyo, Japan), September 2–8, 2011ISTCP-VIII: Professor Péter Surján, Eötvös (Budapest, Hungary), August 25–31, 2013ISTCP-IX: Professor Mark Hoffmann, Grand Forks (ND, USA), July 17–22, 2016For the 10th congress of the ISTCP, there were 543 participants from all around the world. The program consisted of 200 lectures and almost 280 poster presentations, allowing the participants to get a broad view of the most recent advances in almost all subject matters in the field of theoretical chemical physics. With the city of Tromsø being located north of the Arctic Circle, the sun never set during the entire conference, creating a unique and stimulating atmosphere for scientific discussions.The International Society for Theoretical Chemical Physics (ISTCP) was founded in 1990 by Professor János Ladik at the University of Erlangen, Germany. ISTCP has the objectives to promote theoretical developments at the frontier between physics and chemistry. Additionally the goal is to allow younger researchers to interact with leading contributors in the field at regularly organized International Congresses. The Society involves an Honorary Board, a Board of Directors gathering altogether about 60 scientists (including five Nobel Laureates and two Wolf Prize laureates) in the fields of Theoretical Chemistry and Physics, and a Board of National Representatives covering about 35 countries/regions. The current President, since July 2000, is Professor Erkki J. Brändas, from Uppsala University, Sweden.ISTCP congress proceedings have been published regularly in the special issues of the International Journal of Quantum Chemistry (IJQC) and partly (2002, 2008) copublished in special volumes of Progress in Theoretical Chemistry and Physics (PTCP). For the 10th congress, we are very happy to be able to collect a small sample of the science presented at the ISTCP-X as a collection in Advances in Quantum Chemistry. These articles were solicited from researchers in several forefront fields represented at ISTCP-X.The articles cover topics from very accurate calculations using multireference perturbation theories and high-accuracy studies going beyond the Born-Oppenheimer approximation, through the study of interaction of light with molecules and materials—from very short attosecond processes to photophysical processes in chemical and biological systems—to the nature of excited states in anionic systems and the temperature dependence of the mobility of rubrene. Parity violation, fundamental symmetries, and tunneling effects are also covered and the power of machine learning in quantum chemistry is addressed in other chapters. Finally, Maximillian Seel provides some reminiscences of the founder of the ISTCP, Prof. Janos Ladik, who sadly passed away on March 17, 2018.ISTCP-X was organized into 13 thematic symposia, plus a special symposium honoring the late founder of the ISTCP, Prof. Janos Ladik, organized into a set of plenary and keynote lectures as well as parallel sessions covering contributions from the thematic symposia. The very compact conference venue made conversation across disciplines and thematic symposia easy to organize. The coorganizers of each of the symposia had significant freedom in inviting leading scientists in their areas, with attention paid to overall geographical, career stage, and gender balance. It is the careful thought and hard work of the Symposium Organizers that contributed to the success of the congress. The Symposia and their Organizers were:1.From picoseconds to attoseconds: nuclear and electron dynamics (David Clary, Leticia Gonzalez, Fernando Martin)2.Aspects of heavy-element chemistry (Pekka Pyykkö, Trond Saue)3.Emergent electronic structure methods (Stefan Goedecker, Gustavo Scuseria)4.Multiscale modeling including focused models (Benedetta Mennucci, Lyudmila Slipchenko)5.Large-scale electronic structure models of materials (Thomas Heine, Hiromi Nakai)6.Ultracold chemical physics (Jeremy M. Hutson, Bogumil Jeziorski)7.Molecular properties and interactions (Antonio Rizzo, Krzysztof Szalewicz)8.Computational spectroscopy: From X-rays to microwaves (Attila Csaszar, Hans Ågren)9.90 years of r12: Hylleraas symposium (Wim Klopper, Ed Valeev)10.Machine-learning and data-driven approaches in chemical physics (Alán Aspuru-Guzik, Pavlo Dral)11.Computational biophysics (Fernanda Duarte, Ursula Röthlisberger)12.Path-integral methods (David E. Manolopoulos, Gregory Voth)13.Physical organic chemistry and catalysis (Odile Eisenstein, Vidar R. Jensen)14.Janos Ladik memorial symposium (Erkki Brändas, Kenneth Ruud)In addition to symposia, there were 12 plenary and keynote talks for which all participants were gathered.1.Sharon Hammes-Schiffer, Multicomponent Quantum Chemistry: Integrating Electronic and Nuclear Quantum Effects2.Trygve Helgaker, Egil Hylleraas—A Pioneer of Computational Quantum Mechanics3.Peter Schwerdtfeger, The Year of the Periodic Table—Going Superheavy4.Sylvio Canuto, Environment Contribution to Molecular Spectroscopy, Reactivity and Photochemistry5.Peter Gill, Q-MP2-OS: A New Approach to Correlation Using Quadrature6.Peter Saalfrank, Molecules Driven by Light: Electron and Nuclear Dynamics7.Thomas F. Miller, Classical and Machine-Learning Methods for Quantum Simulation8.Irene Burghardt, High-Dimensional Quantum Dynamics of Functional Organic Polymer Materials: Coherence, Confinement, and Disorder9.Giulia Galli, Simulating Energy Conversion Processes From First Principles10.Zhigang Shuai, Density Matrix Renormalization Group: Time-Dependent Formalism, Light-Emitting, Carrier Transport, and Singlet Fission11.Monica Olvera de la Cruz, Properties of Molecular Electrolytes12.Kersti Hermansson, OH, Seriously, … Molecules + Materials = Difficult!We are grateful to all organizers for their exceptional work. We are indebted to our excellent scientific organizing committee that guided us in producing a well-balanced, global perspective on cutting-edge chemical physics: Aurora Clark, David Clary, Hazel Cox, Peter Gill, Leticia Gonzalez, Kersti Hermansson, Bogumil Jeziorski, Anna Krylov, Shuhua Li, Hiromi Nakai, Oleg Prezhdo, and Thereza Soares, and the local organizing committee: Maarten Beerepoot, Bjørn-Olav Bransdal, Stig Eide, Luca Frediani, Bin Gao, Stephanie Hansen, Kathrin Hopmann, and Michal Repisky. Many thanks also to Karen Dundas for designing the logo of the congress. We are also grateful to all session chairs, speakers, poster presenters, as well as all student volunteers, contributing significantly to the great success of the meeting. For more details regarding the congress we refer to the web site of the congress, http://istcp-2019.org/.The ISTCP-X congress took place at the Clarion Hotel The Edge in downtown Tromsø, located less than 5 km away from the local airport. The compact city center made it easy for participants to engage in discussions in restaurants and cafes, and gave a sense of a workshop with time and space for scientific discussions despite the large number of conference participants. The beautiful surroundings of the city and the never-ending days was exploited by many of the participants, who used the late evenings or early mornings to explore the surroundings through bicycle or hiking trips.We are pleased to express our sincere thanks to our sponsors. We would here in particular like to thank the Research Council of Norway and the University of Tromsø—The Arctic University of Norway for very generous financial support, and the staff at Clarion Hotel The Edge for making sure all practical aspects of the conference went smoothly. We are also grateful to ACS Omega, Journal of Chemical Theory and Computation, The Journal of Physical Chemistry, The Journal of Physical Chemistry Letters, PCCP, International Journal of Quantum Chemistry, Journal of Computational Chemistry, and Elsevier through Advances in Quantum Chemistry for providing poster awards for young researchers. The poster prize winners were selected by the members of the scientific committee, and we are grateful to our sponsors for allowing us to honor many young scientists for their excellent poster contributions at the conference.The guest editors of this special volume, finally, want to thank the authors, who accepted our invitation to contribute to these proceedings, and in so doing provide a perspective of some cutting-edge areas of study in chemical physics. The Xth congress of ISTCP included both these areas and many more. We hope that all researchers with a great interest in theory and methods related to fundamental scientific problems and future progress in our field will appreciate this volume.
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