bluuebunny/crossref_metadata_2025 huggingface dataset:
Goethe the Alchemist
Authors: Gray Ronald Douglas
Published: January 2011

In his autobiography, Goethe half-apologetically admits the youthful enthusiasm he experienced for alchemical and mystical readings: Georg von Welling's obscure Opus Mago-Cabbalisticum et Theosophicum and the anonymously published Aurea Catena Homeri, as well as works by Paracelsus, Basilis Valentinus and van Helmont. Originally published in 1952, this study shows how the symbols and concepts of alchemy played a key role in the genesis of Goethe's later works, both scientific and literary. Author of, among other books on German literature, Goethe: A Critical Introduction (1967) and An Introduction to German Poetry (1965), Ronald D. Gray details Goethe's alchemical readings, and shows how these influences were processed and transformed into a unique blend of scientific and poetic accounts of reality. Unprecedented in its approach, this study will be of interest to readers of German literature, as well as to anyone interested in the history and evolution of mysticism.
Die Staatshaushaltung der Athener
Authors: Boeckh August
Published: January 2011

August Boeckh's work, first published in 1817, is still regarded as one of the most thorough treatments of the economic structures of Athenian society. Boeckh makes exhaustive use of the epigraphical and literary sources he has at his disposal and covers a wide range of topics. In Volume 1 he addresses the main areas of the Athenian economic infrastructure, beginning with an account of silver and gold as the general currency. He writes about the income needed by the individual citizen in order to sustain a reasonable living standard, the clothes available to him, and his diet. He investigates the cost of the cult of the gods, and the funds spent on maintaining Athens as a military power. He also explains tax brackets, and gives examples of different categories of fines, as well as examining Xenophon's plan to improve general prosperity. This reissue is of the 1886 edition.
English for Academic Purposes
Authors: Jordan R. R.
Published: January 2011

English for Academic Purposes provides a comprehensive overview of the field of English for Academic Purposes (EAP) for teachers. It not only looks at study skills, but also at other central concerns of EAP, such as needs analysis, syllabus and course design, methodology and materials, learning styles, tests and exams, and academic style and genre analysis. In addition to general EAP, the author also considers subject-specific language and the production of teaching materials. Throughout, the author adopts a user-friendly approach in which theoretical considerations are balanced with practical experience. Issues are discussed and illustrated, but readers are also encouraged to form their own opinions by means of stimulating introspect and discuss sections at the end of each chapter.
The Mechanism of Human Facial Expression
Authors: Duchenne de Boulogne G. -B.
Published: January 2011

In Mécanisme de la physionomie humaine, the great nineteenth-century French neurologist Duchenne de Boulogne combined his intimate knowledge of facial anatomy with his skill in photography and expertise in using electricity to stimulate individual facial muscles to produce a fascinating interpretation of the ways in which the human face portrays emotions. This book was pivotal in the development of psychology and physiology as it marked the first time that photography had been used to illustrate, and therefore 'prove', a series of experiments. In this volume, Andrew Cuthbertson has provided an English translation of Duchenne, complete with a reproduction of the marvellous Album of photographs. The four commentary chapters by modern experts describe the relevance of Duchenne's findings to the fields of experimental psychology, plastic surgery, neurology and physiology. This book will therefore be valued by all those who deal with facial expression, including psychologists, physicians and those involved in the fine arts and photography.
Sino-Tibetan
Authors: Benedict Paul K.
Published: January 2011

A comprehensive account of the Sino-Tibetan, a language stock comparable in size and diversification to Indo-European and comprising Chinese, Karen and over a hundred Tibetan-Burman languages. Dr Benedict presents a systematic analysis of the morphology and phonology of the main descendants of the stock, traces their family relationships and reconstructs in outline the parent language, Sino-Tibetan. There is a glossary of Tibeto-Burman index, which should prove of especial value as a working tool for scholars. Although the book was first drafted many years ago, Dr Benedict made extensive annotations on the original manuscript and Professor James A. Matisoff added many notes on bibliography and the Burmese-Lolo group of languages. The scope and original theses of the work, however, remain unaltered and the editors present it as a major and original contribution to the study of oriental linguistics.
Antarctic Marine Geology
Authors: Anderson J. B.
Published: January 2011

The fragile Antarctic environment consists of a closely linked system of the lithosphere, atmosphere, cryosphere, hydrosphere and biosphere. Changes in this system have influenced global climate, oceanography and sea level for most of Cenozoic time. The geological history of this region therefore provides a special record of important interactions between the various components of the Earth System. Antarctic Marine Geology is a comprehensive single-authored book to introduce students and researchers to the geological history of the region and the unique processes that occur there. Research literature on the region is widely disseminated. The book is intended as a reference for all scientists working in Antarctica, and will also serve as a textbook for graduate courses in Antarctic marine geology.
Imperial Sceptics
Authors: Claeys Gregory
Published: January 2011

Imperial Sceptics provides a highly original analysis of the emergence of opposition to the British Empire from 1850–1920. Departing from existing accounts, which have focused upon the Boer War and the writings of John Hobson, Gregory Claeys proposes a new chronology for the contours of resistance to imperial expansion. Claeys locates the impetus for such opposition in the late 1850s with the British followers of Auguste Comte. Tracing critical strands of anti-imperial thought through to the First World War, Claeys then scrutinises the full spectrum of socialist writings from the early 1880s onwards, revealing a fundamental division over whether a new conception of 'socialist imperialism' could appeal to the electorate and satisfy economic demands. Based upon extensive archival research, and utilising rare printed sources, Imperial Sceptics will prove a major contribution to our understanding of nineteenth-century political thought, shedding new light on theories of nationalism, patriotism, the state and religion.
Enterprise Cloud Computing
Authors: Shroff Gautam
Published: January 2011

Cloud computing promises to revolutionize IT and business by making computing available as a utility over the internet. This book is intended primarily for practising software architects who need to assess the impact of such a transformation. It explains the evolution of the internet into a cloud computing platform, describes emerging development paradigms and technologies, and discusses how these will change the way enterprise applications should be architected for cloud deployment. Gautam Shroff provides a technical description of cloud computing technologies, covering cloud infrastructure and platform services, programming paradigms such as MapReduce, as well as 'do-it-yourself' hosted development tools. He also describes emerging technologies critical to cloud computing. The book also covers the fundamentals of enterprise computing, including a technical introduction to enterprise architecture, so it will interest programmers aspiring to become software architects and serve as a reference for a graduate-level course in software architecture or software engineering.
Numbers, Groups and Codes
Authors: Humphreys J. F. , Prest M. Y.
Published: January 2011

This textbook is an introduction to algebra via examples. The book moves from properties of integers, through other examples, to the beginnings of group theory. Applications to public key codes and to error correcting codes are emphasised. These applications, together with sections on logic and finite state machines, make the text suitable for students of computer science as well as mathematics students. Attention is paid to historical development of the mathematical ideas. This second edition contains new material on mathematical reasoning skills and a new chapter on polynomials has been added. The book was developed from first-level courses taught in the UK and USA. These courses proved successful in developing not only a theoretical understanding but also algorithmic skills. This book can be used at a wide range of levels: it is suitable for first- or second-level university students, and could be used as enrichment material for upper-level school students.
Probability and Statistics by Example
Authors: Suhov Yuri , Kelbert Mark
Published: January 2011

Probability and Statistics are as much about intuition and problem solving as they are about theorem proving. Because of this, students can find it very difficult to make a successful transition from lectures to examinations to practice, since the problems involved can vary so much in nature. Since the subject is critical in many modern applications such as mathematical finance, quantitative management, telecommunications, signal processing, bioinformatics, as well as traditional ones such as insurance, social science andengineering, the authors have rectified deficiencies in traditional lecture-based methods by collecting together a wealth of exercises with complete solutions, adapted to needs and skills of students. Following on from the success of Probability and Statistics by Example: Basic Probability and Statistics, the authors here concentrate on random processes, particularly Markov processes, emphasising modelsrather than general constructions. Basic mathematical facts are supplied as and when they are needed andhistorical information is sprinkled throughout.
String Theory and M-Theory
Authors: Becker Katrin , Becker Melanie , Schwarz John H.
Published: January 2011

String theory is one of the most exciting and challenging areas of modern theoretical physics. This book guides the reader from the basics of string theory to recent developments. It introduces the basics of perturbative string theory, world-sheet supersymmetry, space-time supersymmetry, conformal field theory and the heterotic string, before describing modern developments, including D-branes, string dualities and M-theory. It then covers string geometry and flux compactifications, applications to cosmology and particle physics, black holes in string theory and M-theory, and the microscopic origin of black-hole entropy. It concludes with Matrix theory, the AdS/CFT duality and its generalizations. This book is ideal for graduate students and researchers in modern string theory, and will make an excellent textbook for a one-year course on string theory. It contains over 120 exercises with solutions, and over 200 homework problems with solutions available on a password protected website for lecturers at www.cambridge.org/9780521860697.
The Cambridge Medical Ethics Workbook
Authors: Dickenson Donna , Huxtable Richard , Parker Michael
Published: January 2011

This new edition of The Cambridge Medical Ethics Workbook builds on the success of the first edition by working from the 'bottom up', with a widely praised case-based approach. A variety of guided exercises are supplemented by short papers and commentaries on legal and ethical issues, challenging readers to develop their own analyses and recommendations. Chapters cover death, genetics, new reproductive technologies, research, long-term care, mental health, children and young people, allocation of scarce resources, and general issues about autonomy and patient choice. An appendix discusses the use of this book in teaching, along with a full bibliography, list of Kennedy Institute keywords, and suggestions for further reading. An interactive CD-ROM packaged with the book provides extra cases, a glossary, legal references and the chance to record a personal learning diary. Its simple, clear style makes this book ideal for individual reference and as a set text for group teaching.
Manual of Inpatient Psychiatry
Authors: Casher Michael I. , Bess Joshua D.
Published: January 2011

Inpatient units treat some of the most difficult psychiatric patients. This compact clinical manual is convenient for use on the ward and serves as a standard guide for treatment, addressing the common questions and issues that clinicians face in day-to-day psychiatric work with this challenging patient group. Chapters are organised around the diagnoses found on inpatient psychiatric units, with additional chapters addressing documentation and the care of young adult inpatients. Charts, tables and clinical hints amplify the text, allowing practising clinicians to find the information they need quickly and easily, and enabling students to master the field for board and end-of-clerkship exams. This practical manual is essential reading for practising psychiatrists, psychiatric residents and all psychiatric educators, as well as serving as an accessible reference for physicians in other specialties who consult on the psychiatric ward, psychiatric nurses and medical students.
Dietaryl-arginine supplementation enhances intestinal development and expression of vascular endothelial growth factor in weanling piglets
Authors: Yao Kang , Guan Shu , Li Tiejun , Huang Ruilin , Wu Guoyao , Ruan Zheng , Yin Yulong
Published: January 2011

Oral administration ofl-arginine has been reported to prevent gut disease in human infants. However, little is known about the effects of dietary arginine supplementation on intestinal development of weaned piglets. In the present study, twenty 21-d-old castrated piglets with 5·3 (sem0·13) kg body weight (BW) were weaned from sows, individually housed and randomly assigned to one of the two maize- and soyabean meal-based diets supplemented with 0 or 1 %l-arginine. After consuming the diets for 7 d, six pigs were randomly selected from each group to obtain various tissues. Compared with control pigs, dietary supplementation with 1 %l-arginine did not affect feed intake but enhanced (P < 0·05) the relative weight of the small intestine (+33 %), daily BW gain (+38 %) and feed efficiency (+28 %). The villus height of the duodenum, jejunum and ileum in arginine-supplemented piglets was 21, 28 and 25 % greater (P < 0·05) than in the non-supplemented control group. Arginine supplementation increased (P < 0·05) protein levels for vascular endothelial growth factor (VEGF) in duodenal, jejunal and ileal mucosae by 14, 39 and 35 %, respectively. Compared with the control group, dietary supplementation with 1 %l-arginine increased (P < 0·05) plasma concentrations of arginine and insulin (+36 %), and decreased (P < 0·05) plasma concentrations of cortisol ( − 33 %), NH3( − 21 %) and urea ( − 19 %). These results indicate that arginine supplementation enhances intestinal growth, development and expression of VEGF in early-weaned pigs fed a maize- and soyabean meal-based diet. The findings may have important implications for neonatal pigs under stressful or diseased conditions.
Predicting the aftermath of vortex breakup in rotating flow
Authors: CARNEVALE G. F. , KLOOSTERZIEL R. C. , ORLANDI P. , van SOMMEREN D. D. J. A.
Published: January 2011

A method for predicting the outcome of vortex breakup in a rotating flow is introduced. The vortices dealt with here are subject to both centrifugal and barotropic instabilities. The prediction of the aftermath of the breakup relies on knowing how both centrifugal and barotropic instabilities would equilibrate separately. A theoretical model for non-linear equilibration in centrifugal instability is wedded to two-dimensional simulation of barotropic instability to predict the final vortices that emerge from the debris of the original vortex. This prediction method is tested against three-dimensional Navier–Stokes simulations. For vortices in which a rapid centrifugal instability triggers a slower barotropic instability, the method is successful both qualitatively and quantitatively. The skill of the prediction method decreases as the time scales of the two instabilities become comparable.
Conscientious Refusals by Hospitals and Emergency Contraception
Authors: WICCLAIR MARK R.
Published: January 2011

Hospitals sometimes refuse to provide goods and services or honor patients’ decisions to forgo life-sustaining treatment for reasons that appear to resemble appeals to conscience. For example, based on the Ethical and Religious Directives for Catholic Health Care Services (ERD), Catholic hospitals have refused to forgo medically provided nutrition and hydration (MPNH), and Catholic hospitals have refused to provide emergency contraception (EC) and perform abortions or sterilization procedures. I consider whether it is justified to refuse to offer EC to victims of sexual assault who present at the emergency department (ED). A preliminary question, however, is whether a hospital’s refusal to provide services can be conceptualized as conscience based.
Pioneers in Optics: Jean-Bernard-Leon Foucault and Willebrord Snell
Authors: Davidson Michael W.
Published: January 2011

Jean-Bernard-Leon Foucault was a French physicist who is considered one of the most versatile experimentalists of the nineteenth century. He is well known for his experiments in optics and mechanics and was involved in the development of a method to measure the speed of light with extreme accuracy. Foucault is most often remembered for proving, with the use of a pendulum, that the Earth rotates on its axis.
Raising the Standard of Specimen Preparation for Aberration-Corrected TEM and STEM
Authors: Cerchiara R. R. , Fischione P. E. , Liu J. , Matesa J. M , Robins A. C. , Fraser H. L. , Genc A.
Published: January 2011

With the recent advances made in monochromation of electron sources and Cs-correction, the point resolution of the transmission electron microscope (TEM) has been extended into the sub-Angstrom regime. This development has led to an important consequence—that specimen preparation has become a more critical issue for the materials scientist. Nanoscale artifacts that could be tolerated a few years ago when imaging in the 0.1–0.15 nm range can no longer be allowed. An example is hydrocarbon contamination, which although only a few monolayers thick, obscures the area of interest. Other examples include residual deformation and oxidation following traditional mechanical methods. Ion-based methods may induce amorphization and implantation defects, depending on the type of ion, its energy, and the particular protocol that is used.
Tools for Electron Diffraction Pattern Simulation for the Powder Diffraction File
Authors: Reid Joel , Crane David , Blanton Justin , Crowder Cyrus , Kabekkodu Soorya , Fawcett Tim
Published: January 2011

Since the creation of the Joint Committee on Powder Diffraction Standards (JCPDS) over sixty years ago, the Powder Diffraction File (PDF) has been the key source of standard powder diffraction data for identification and analysis of materials of all types, from natural minerals and high-tech ceramics to metals and alloys and pharmaceuticals. Although this editorially reviewed database has been the mainstay for diffraction pattern reference for the x-ray powder diffraction community, recent developments provide information and tools for electron diffraction. In recent years, the International Centre for Diffraction Data (ICDD, formerly JCPDS) has transformed the flat-file format of the PDF to a more flexible relational database (RDB) format. The PDF has been greatly expanded to include calculated patterns from multiple collaborating databases, including the Inorganic Crystal Structure Database (FIZ Karlsruhe, Germany), the Linus Pauling File (MPDS, Vitznau, Switzerland), and the Cambridge Structural Database (CCDC, Cambridge, United Kingdom). A significant portion of its entries include atomic coordinates and a specific database dedicated to organic phases exists. All new entries for the ICDD databases undergo over 100 quality checks before inclusion, and a quality mark is assigned for each entry that passes.
One of my Failures: Diffraction in the TEM
Authors: Eades Alwyn
Published: January 2011

There are two principal techniques for obtaining diffraction patterns in the transmission electron microscope (TEM). They are selected-area diffraction (SAD) and convergent-beam diffraction (CBED). CBED is quicker and easier to use, and it provides a much richer characterization of the sample. Thus, it is clear that CBED should be used in the vast majority of cases. It should be the diffraction technique that students learn first, and students should be taught to consider it the standard method of doing diffraction in the TEM.
Microscopy Y'All: A Preview of M&M 2011 in Nashville
Authors: Giovannucci David
Published: January 2011

Microscopy & Microanalysis (M&M) is the annual meeting for the Microscopy Society of America, the Microbeam Analysis Society, and the International Metallographic Society, Inc. This is the premier conference for microscopists working in the physical, life, and analytical sciences.
White House Issues Scientific Integrity Policies
Authors: Showstack Randy
Published: January 2011

On 17 December the White House issued its long‐awaited guidelines on the Obama administration's scientific integrity policy.

The new memorandum to heads of departments and agencies of the U.S. federal government “describes the minimum standards expected as departments and agencies craft scientific integrity rules appropriate for their particular missions and cultures, including a clear prohibition on political interference in scientific processes and expanded assurances of transparency,” according to Presidential Science Advisor John Holdren, who released the guidelines. Holdren also is the director of the White House Office of Science and Technology Policy (OSTP). The guidelines require “that department and agency heads report to me on their progress toward completing those rules within 120 days.”
Improving the Accuracy of Estimation of Climate Extremes: Workshop on Metrics and Methodologies of Estimation of Extreme Climate Events; Paris, France, 27–29 September 2010
Authors: Zolina Olga , Detemmerman Valery , Trenberth Kevin E.
Published: January 2011

Climate projections point toward more frequent and intense weather and climate extremes such as heat waves, droughts, and floods, in a warmer climate. These projections, together with recent extreme climate events, including flooding in Pakistan and the heat wave and wildfires in Russia, highlight the need for improved risk assessments to help decision makers and the public. But accurate analysis and prediction of risk of extreme climate events require new methodologies and information from diverse disciplines. A recent workshop sponsored by the World Climate Research Programme (WCRP) and hosted at United Nations Educational, Scientific and Cultural Organization (UNESCO) headquarters in France brought together, for the first time, a unique mix of climatologists, statisticians, meteorologists, oceanographers, social scientists, and risk managers (such as those from insurance companies) who sought ways to improve scientists' ability to characterize and predict climate extremes in a changing climate.
Schlitzer Receives Ocean Sciences Award
Authors: Hansell Dennis A. , Schlitzer Reiner
Published: January 2011

Reiner Schlitzer received the 2010 Ocean Sciences Section Award at the 2010 Ocean Sciences Meeting, held 22–26 February 2010 in Portland, Oreg. The award is given in recognition of outstanding and long‐standing service to the ocean sciences.
Range and Richness of Vascular Land Plants: The Role of Variable Light
Authors: Schultz Colin
Published: January 2011

The observation that the number of species decreases—while at the same time the average range of local species increases—with increasing latitude is known within ecological circles as Rapoport's rule. In the AGU monograph Range and Richness of Vascular Land Plants: The Role of Variable Light, former AGU president Peter S. Eagleson seeks a cause for Rapoport's rule. Using a tightly focused analysis, Eagleson delves into the complex interactions that govern ecosystems to propose the primary importance to range and richness of one key variable, the locally incident shortwave radiation. In this interview, Eos talks with Eagleson.
Ultrafast charge separation driven by differential particle and hole mobilities
Authors: Dutoi Anthony D. , Wormit Michael , Cederbaum Lorenz S.
Published: January 2011

The process of a local excitation evolving into an intramolecular charge-separated state is followed and compared for several systems by directly simulating the time propagation of the electronic wavefunction. The wavefunction and Hamiltonian are handled using the extended second-order algebraic diagrammatic construction (ADC(2)-x), which explicitly accounts for electron correlation in the dynamic many-particle state. The details of the charge separation can be manipulated according to the chemical composition of the system; atoms which dope the conjugated system with either particles or holes are shown to effect whether the particle or hole is more mobile. Initially, the charges oscillate between the ends of linear molecules (with different rates), separating periodically, but, at long times, both charges tend to spread over the whole molecule. Charge separation is also shown to occur for asymmetric systems, where it may eventually be experimentally feasible to excite a localized resonance (nonstationary state) on one end of the molecule preferentially and follow the ensuing dynamics.
Temperature-ramping measurement of dye reorientation to probe molecular motion in polymer glasses
Authors: Paeng Keewook , Lee Hau-Nan , Swallen Stephen F. , Ediger M. D.
Published: January 2011

A temperature-ramping anisotropy measurement is introduced as an efficient way to study molecular motion in polymer glasses. For these experiments, fluorescent molecules were dispersed in the polymer glass and the reorientation of these dyes was used as a probe of segmental dynamics. For thick samples of polystyrene, poly (4-tert-butyl styrene), and poly(2-vinyl pyridine), temperature-ramping anisotropy measurements have a shape similar to differential scanning calorimetry measurements and nearly the same transition temperature. We present results using different fluorescent molecules and different temperature-ramping rates; such experiments show potential for accessing slow molecular motions considerably below Tg. Temperature-ramping anisotropy measurements were performed on freestanding poly (4-tert-butyl styrene) films of varying thicknesses. The anisotropy decay of a 22 nm film was shifted about 12 K lower in temperature as compared to a bulk sample.
Single molecules reveal the dynamics of heterogeneities in a polymer at the glass transition
Authors: Bingemann Dieter , Allen Rachel M. , Olesen Scott W.
Published: January 2011

The notion of heterogeneous dynamics in glasses, that is, the spatial and temporal variations of structural relaxation rates, explains many of the puzzling features of glass dynamics. The nature and the dynamics of these heterogeneities, however, have been very controversial. Single rhodamine B molecules in poly(vinyl acetate) at the glass transition reorient through sudden jumps. With a statistical search for the most likely break points in the logarithm of the ratio of the two perpendicular fluorescence polarizations, we determine the times of these angular jumps. We interpret these jumps as an indication for individual glass rearrangements in the vicinity of the probe molecule. Time-series analysis of the resulting sequence of waiting times between jumps shows that dynamic heterogeneities in the matrix exist, but are short lived. From the correlation of the logarithm of the waiting time between subsequent jumps, we determine an upper limit for the lifetime of heterogeneities in the sample. The correlation time of τhet = 32 s is three times shorter than the orientational correlation time of the probe molecule, τorient = 90 s, in the sample at this temperature, but 13 times longer than the structural relaxation time, τα = 2.5 s, estimated for this sample from dielectric experiments. We present a model for glass dynamics in which each rearrangement in one region causes a random change in the barrier height for subsequent rearrangements in a neighboring region. This model, which equates the dynamics of the heterogeneities with the dynamics of the glass itself and thus implies a factor of one between heterogeneity lifetime and structural relaxation time, successfully reproduces the statistics of the experimentally observed waiting time sequences.
Simple and effective application of the Wang–Landau method for multicanonical molecular dynamics simulation
Authors: Shimoyama Hiromitsu , Nakamura Haruki , Yonezawa Yasushige
Published: January 2011

We propose a novel application of the Wang–Landau method (WLM) for multicanonical molecular dynamics (McMD) simulations. Originally, WLM was developed for Monte Carlo (MC) simulations. Fundamentally, WLM remarkably reduces simulation efforts because it estimates the optimal multicanonical energy function automatically. When WLM is applied to McMD, not only the multicanonical energy but also energy gradient must be estimated adequately. However, because of the rugged multicanonical energy function at the early simulation stage, applications of WLM for MD simulations are difficult and require a smoothing procedure: simulation efforts such as cubic-spline extrapolation and gathering multiple preruns are utilized for smoothing. We propose a simple and effective smoothing method that requires only one additional equation and two time-dependent parameters. As a result, our method produced the correct multicanonical energy function and succeeded in the flat sampling of a small biomolecule with reduced simulation effort.
Demonstration and interpretation of significant asymmetry in the low-resolution and high-resolution Q
y fluorescence and absorption spectra of bacteriochlorophyll a
Authors: Rätsep Margus , Cai Zheng-Li , Reimers Jeffrey R. , Freiberg Arvi
Published: January 2011

Low- and high-resolution absorption and fluorescence emission Qy spectra of bacteriochlorophyll a (BChl a) were recorded, along with homogeneous band line shapes, revealing significant asymmetry between the absorption and emission profiles that are interpreted using a priori spectral calculations. The spectra were recorded in a range of organic solvents facilitating both penta- and hexa-coordination of Mg at ambient and cryogenic temperatures. Detailed vibrational structure in the ground electronic state, virtually independent of Mg coordination, was revealed at 4.5 K by a hole-burning fluorescence line-narrowing technique, complementing the high-resolution spectrum of the excited state measured previously by hole burning to provide the first complete description of the Qy absorption and fluorescence spectra of BChl a. Spectral asymmetry persists from 4.5 to 298 K. Time-dependent density-functional theory calculations of the gas-phase absorption and emission spectra obtained using the CAM-B3LYP density functional, curvilinear coordinates, and stretch-bend-torsion scaling factors fitted to data for free-base porphyrin quantitatively predict the observed frequencies of the most-significant vibrational modes as well as the observed absorption/emission asymmetry. Most other semi-empirical, density-functional, and ab initio computational methods severely overestimate the electron-vibrational coupling and its asymmetry. It is shown that the asymmetry arises primarily through Duschinsky rotation.
Effects of heme on the thermal stability of mesophilic and thermophilic cytochromes c: Comparison between experimental and theoretical results
Authors: Oda Koji , Kodama Ryota , Yoshidome Takashi , Yamanaka Masaru , Sambongi Yoshihiro , Kinoshita Masahiro
Published: January 2011

We have recently proposed a measure of the thermal stability of a protein: the water-entropy gain at 25 °C upon folding normalized by the number of residues, which is calculated using a hybrid of the angle-dependent integral equation theory combined with the multipolar water model and the morphometric approach. A protein with a larger value of the measure is thermally more stable. Here we extend the study to analyses on the effects of heme on the thermal stability of four cytochromes c (PA c551, PH c552, HT c552, and AA c555) whose denaturation temperatures are considerably different from one another despite that they share significantly high sequence homology and similar three-dimensional folds. The major conclusions are as follows. For all the four cytochromes c, the thermal stability is largely enhanced by the heme binding in terms of the water entropy. For the holo states, the measure is the largest for AA c555. However, AA c555 has the lowest packing efficiency of heme and the apo polypeptide with hololike structure, which is unfavorable for the water entropy. The highest stability of AA c555 is ascribed primarily to the highest efficiency of side-chain packing of the apo polypeptide itself. We argue for all the four cytochromes c that due to covalent heme linkages, the number of accessible conformations of the denatured state is decreased by the steric hindrance of heme, and the conformational-entropy loss upon folding becomes smaller, leading to an enhancement of the thermal stability. As for the apo state modeled as the native structure whose heme is removed, AA c555 has a much larger value of the measure than the other three. Overall, the theoretical results are quite consistent with the experimental observations (e.g., at 25 °C the α-helix content of the apo state of AA c555 is almost equal to that of the holo state while almost all helices are collapsed in the apo states of PA c551, PH c552, and HT c552).
Visualizing electron correlation by means of ab initio scanning tunneling spectroscopy images of single molecules
Authors: Toroz Dimitrios , Rontani Massimo , Corni Stefano
Published: January 2011

Scanning tunneling microscopy (STM) has been a fundamental tool to characterize many-body effects in condensed matter systems, from extended solids to quantum dots. STM of molecules decoupled from the supporting conductive substrate has the potential to extend STM characterization of many-body effects to the molecular world as well. In this paper, we describe a many-body tunneling theory for molecules decoupled from the STM substrate, and we report on the use of standard quantum chemical methods to calculate the quantities necessary to provide the “correlated” STM molecular image. The developed approach has been applied to 18 different molecules to explore the effects of their chemical nature and of their substituents, as well as to verify the possible contribution by transition metal centers. Whereas the bulk of calculations has been performed with the configuration interaction method with single and double excitations (CISD), because of the computational cost some tests have been also performed with the more accurate coupled cluster with single and double excitations (CCSD) method to quantify the importance of the computational level on many-body STM images. We have found that correlation induces a remarkable squeezing of the images, and that correlated images are not derived from Hartree–Fock HOMO or LUMO alone, but include contributions from other orbitals as well. Although correlation effects are too small to be resolved by present STM experiments for the studied molecules, our results provide hints for seeking out other species with larger, and possibly experimentally detectable, correlation effects.
High-resolution electron spectroscopy, preferential metal-binding sites, and thermochemistry of lithium complexes of polycyclic aromatic hydrocarbons
Authors: Lee Jung Sup , Krasnokutski Serge A. , Yang Dong-Sheng
Published: January 2011

Polycyclic aromatic hydrocarbons are model systems for studying the mechanisms of lithium storage in carbonaceous materials. In this work, Li complexes of naphthalene, pyrene, perylene, and coronene were synthesized in a supersonic metal-cluster beam source and studied by zero-electron-kinetic-energy (ZEKE) electron spectroscopy and density functional theory calculations. The adiabatic ionization energies of the neutral complexes and frequencies of up to nine vibrational modes in the singly charged cations were determined from the ZEKE spectra. The metal-ligand bond energies of the neutral complexes were obtained from a thermodynamic cycle. Preferred Li/Li+ binding sites with the aromatic molecules were determined by comparing the measured spectra with theoretical calculations. Li and Li+ prefer the ring-over binding to the benzene ring with a higher π-electron content and aromaticity. Although the ionization energies of the Li complexes show no clear correlation with the size of the aromatic molecules, the metal-ligand bond energies increase with the extension of the π-electron network up to perylene, then decrease from perylene to coronene. The trends in the ionization and metal-ligand bond dissociation energies of the complexes are discussed in terms of the orbital energies, local quadrupole moments, and polarizabilities of the free ligands and the charge transfer between the metal atom and aromatic molecules.
Long-range structure of Cu(InxGa1−x)3Se5: A complementary neutron and anomalous x-ray diffraction study
Authors: Lehmann S. , Marrón D. Fuertes , León M. , Feyerherm R. , Dudzik E. , Friedrich E. J. , Tovar M. , Tomm Y. , Wolf C. , Schorr S. , Schedel-Niedrig Th. , Lux-Steiner M. Ch. , Merino J. M.
Published: January 2011

Distinguishing the scattering contributions of isoelectronic atomic species by means of conventional x-ray- and/or electron diffraction techniques is a difficult task. Such a problem occurs when determining the crystal structure of compounds containing different types of atoms with equal number of electrons. We propose a new structural model of Cu(InxGa1−x)3Se5 which is valid for the entire compositional range of the CuIn3Se5–CuGa3Se5 solid solution. Our model is based on neutron and anomalous x-ray diffraction experiments. These complementary techniques allow the separation of scattering contributions of the isoelectronic species Cu+ and Ga3+, contributing nearly identically in monoenergetic x-ray diffraction experiments. We have found that CuIII3Se5 (III=In,Ga) in its room temperature near-equilibrium modification exhibits a modified stannite structure (space group I4¯2m). Different occupation factors of the species involved, Cu+, In3+, Ga3+, and vacancies have been found at three different cationic positions of the structure (Wyckoff sites 2a, 2b, and 4d) depending on the composition of the compound. Significantly, Cu+ does not occupy the 2b site for the In-free compound, but does for the In-containing case. Structural parameters, including lattice constants, tetragonal distortions, and occupation factors are given for samples covering the entire range of the CuIn3Se5–CuGa3Se5 solid solution. At the light of the result, the denotation of Cu-poor 1:3:5 compounds as chalcopyrite-related materials is only valid in reference to their composition.
Base fluid and temperature effects on the heat transfer characteristics of SiC in ethylene glycol/H2O and H2O nanofluids
Authors: Timofeeva Elena V. , Yu Wenhua , France David M. , Singh Dileep , Routbort Jules L.
Published: January 2011

Experimental data are presented for the thermal conductivity, viscosity, and turbulent flow heat transfer coefficient of nanofluids with SiC particles suspended in ethylene glycol (EG)/water (H2O) mixture with a 50/50 volume ratio. The results are compared to the analogous suspensions in water for four sizes of SiC particles (16–90 nm). It is demonstrated that the heat transfer efficiency is a function of both the average particle size and the system temperature. The results show that adding SiC nanoparticles to an EG/H2O mixture can significantly improve the cooling efficiency while water-based nanofluids are typically less efficient than the base fluids. This is one of the few times that substantial nanofluid heat transfer enhancement has been reported in the literature based on a realistic comparison basis of constant velocity or pumping power. The trends important for engineering efficient heat transfer nanofluids are summarized.
Calculations of fine-structure resolved collisional rate coefficients for the NH(X $^{3}\Sigma ^{-}$3Σ−)-He system
Authors: Toboła Robert , Dumouchel Fabien , Kłos Jacek , Lique François
Published: January 2011

We present fine-structure-resolved collisional rate coefficients for the NH(X $^{3}\Sigma ^{-}$3Σ−)-He van der Waals complex. The calculations are based on the state-of-the-art potential energy surface [Cybulski et al., J. Chem. Phys. 122, 094307 (2005)]. Close-coupling calculations of the collisional excitation cross sections of the fine-structure levels of NH by He are calculated for total energies up to 3500 cm $^{-1}$−1, which yield, after thermal average, rate coefficients up to 350 K. The fine-structure splitting of rotational levels is taken into account rigorously. The propensity rules between fine-structure levels are reported, and it is found that F-conserving cross sections are much larger than F-changing cross sections, as expected from theoretical considerations. The calculated rate coefficients are compared with available experimental measurements at room temperature and a fairly good agreement is found between experimental and theoretical data. The agreement confirms the relatively good quality of the scattering calculations and also the accuracy of the potential energy surface used in this work. The new set of thermal rate coefficients for this system may be used for improvements in astrophysical and atmospherical modeling.
Nanoporous metal film: An energy-dependent transmission device for electron waves
Authors: Grech S. , Degiovanni A. , Lapena L. , Morin R.
Published: January 2011

We measure electron transmission through free-standing ultrathin nanoporous gold films, using the coherent electron beam emitted by sharp field emission tips in a low energy electron projection microscope setup. Transmission coefficient versus electron wavelength plots show periodic oscillations between 75 and 850 eV. These oscillations result from the energy dependence of interference between paths through the gold and paths through the nanometer-sized pores of the film. We reveal that these films constitute high transmittance quantum devices acting on electron waves through a wavelength-dependent complex transmittance defined by the porosity and the thickness of the film.
III-V compound semiconductor screening for implementing quantum dot intermediate band solar cells
Authors: Linares P. G. , Martí A. , Antolín E. , Luque A.
Published: January 2011

The intermediate band (IB) concept is regarded as a way of exceeding the Shockley–Queisser efficiency limit through a more efficient use of the solar spectrum. Quantum dots (QDs) have been proposed to achieve a practical implementation of this concept. So far, only few QD material systems, such as In(Ga)As/GaAs and related compounds, have been tested experimentally giving rise to two important conclusions: on the one hand, the verification of the concept fundamentals and on the other hand, the need to seek new QD candidate materials in order to produce high efficiency devices. As regards the latter, in this paper we present an analytical model to assess the potential of QD IB solar cells (IBSCs) consisting of the following steps: (1) calculation of the heterojunction band alignment taking material strain into account, (2) calculation of the QD confined energy levels constituting the IB, and (3) calculation of the efficiency limits in the detailed balance realm and optimization of the QD systems in terms of QD size and material composition. The search criteria are reviewed and three QD systems (InAs/AlxGa1−xAs, InAs1−yNy/AlAsxSb1−x, and InAs1−zNz/Alx[GayIn1−y]1−xP) are identified together with their optimum QD sizes. Efficiencies of over 60% are calculated at maximum light concentration.
Potential curves for inner-shell states of CO calculated at multiconfigurational self-consistent field level
Authors: Rocha Alexandre B.
Published: January 2011

A general strategy to calculate potential curves at multiconfigurational self-consistent field (MCSCF) level for inner-shell states is reported in this paper. Convergence is commonly very tough for inner-shell states, especially at this level of calculation, due to the problem of variational collapse of the inner-shell wave function to the ground or to a low-lying excited state. The present method allows to avoid this drawback by a sequence of constrained optimization in the orbital mixing step. The specific states studied are that resulting from transitions X 1Σ+ → (C 1s−1 π*) 1,3Π of CO. Accurate values are achieved for transition energies and vibrational splittings. A comparison is made with other approach, i.e., inner-shell CI based on a MCSCF wave function optimized for ground or low-lying excited states. This last approach is shown to fail in describing the whole potential curve.
Performance of dynamically weighted multiconfiguration self-consistent field and spin-orbit coupling calculations of diatomic molecules of Group 14 elements
Authors: Zeng Tao , Fedorov Dmitri G. , Klobukowski Mariusz
Published: January 2011

The efficacy of several multiconfiguration self-consistent field (MCSCF) methods in the subsequent spin-orbit coupling calculations was studied. Three MCSCF schemes to generate molecular orbitals were analyzed: state-specific, state-averaged, and dynamically weighted MCSCF. With Sn\documentclass[12pt]{minimal}\begin{document}$_2^{+}$\end{document}2+ as the representative case, we show that the state-specific MCSCF orbitals lead to discontinuities in potential energy curves when avoided crossings of electronic states occur; this problem can be solved using the state-averaged or dynamically weighted MCSCF orbitals. The latter two schemes are found to give similar results when dynamic electron correlation is considered, which we calculated at the level of multiconfigurational quasidegenerate perturbation theory (MCQDPT). We employed the recently developed Douglas–Kroll spin-orbit adapted model core potential, ZFK3-DK3, and the dynamically weighted MCSCF scheme to calculate the spectroscopic constants of the mono-hydrides and compared them to the results obtained using the older set of potentials, MCP-TZP. We also showed that the MCQDPT tends to underestimate the dissociation energies of the hydrides and discussed to what extent coupled-cluster theory can be used to improve results.