Equilibrium Structure of Free Molecules


Book Description

The properties of chemical, pharmaceutical, and biological compounds depend mainly on their molecular structure, whose determination is of fundamental interest. This book examines and systematizes more than three hundred striking structural determinations of free molecules. Featuring high-quality structural data and presenting modern techniques of their determinations by quantum chemistry, high-resolution spectroscopy and electron diffraction, the book is an indispensable resource for graduate students and professional scientists specializing in structural chemistry and other related fields.




Accurate Structure Determination of Free Molecules


Book Description

This book presents a detailed look at experimental and computational techniques for accurate structure determination of free molecules. The most fundamental property of a molecule is its structure – it is a prerequisite for determining and understanding most other important properties of molecules. The determination of accurate structures is hampered by a myriad of factors, subjecting the collected data to non-negligible systematic errors. This book explains the origin of these errors and how to mitigate and even avoid them altogether. It features a detailed comparison of the different experimental and computation methods, explaining their interplay and the advantages of their combined use. Armed with this information, the reader will be able to choose the appropriate methods to determine – to a great degree of accuracy – the relevant molecular structure.




Equilibrium Structure of Free Molecules


Book Description

This book examines around 400 of the most striking examples of structural studies of free molecules—selected and analyzed by virtue of the unique molecular complexity and novelty of the experimental techniques used. The properties of chemical, pharmaceutical, and biological compounds depend mainly on their molecular structure, the determination of which is of fundamental interest. Featuring high-quality structural data determined using modern techniques in electron diffraction and high-resolution spectroscopy, the book is an indispensable resource for graduate students and professional scientists specializing in structural chemistry and other relevant fields.




Equilibrium Molecular Structures


Book Description

Molecular structure is the most basic information about a substance, determining most of its properties. Determination of accurate structures is hampered in that every method applies its own definition of "structure" and thus results from different sources can yield significantly different results. Sophisticated protocols exist to account for these




Chemistry 2e


Book Description

Chemistry 2e is designed to meet the scope and sequence requirements of the two-semester general chemistry course. The textbook provides an important opportunity for students to learn the core concepts of chemistry and understand how those concepts apply to their lives and the world around them. The book also includes a number of innovative features, including interactive exercises and real-world applications, designed to enhance student learning. The second edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Substantial improvements have been made in the figures, illustrations, and example exercises that support the text narrative. Changes made in Chemistry 2e are described in the preface to help instructors transition to the second edition.




Low Temperature Molecular Spectroscopy


Book Description

Molecular spectroscopy has achieved rapid and significant progress in recent years, the low temperature techniques in particular having proved very useful for the study of reactive species, phase transitions, molecular clusters and crystals, superconductors and semiconductors, biochemical systems, astrophysical problems, etc. The widening range of applications has been accompanied by significant improvements in experimental methods, and low temperature molecular spectroscopy has been revealed as the best technique, in many cases, to establish the connection between experiment and theoretical calculations. This, in turn, has led to a rapidly increasing ability to predict molecular spectroscopic properties. The combination of an advanced tutorial standpoint with an emphasis on recent advances and new perspectives in both experimental and theoretical molecular spectroscopy contained in this book offers the reader insight into a wide range of techniques, particular emphasis being given to supersonic jet and matrix isolation techniques, spectroscopy in cryogenic solutions (including liquid noble gases), and in both crystalline and amorphous states. Suitable quantum chemical methods are also considered, as are empirically based force field methods for calculating spectra of large molecular systems. The wide range of topics covered includes: molecular dynamics and reactivity, time-resolved and high-resolution spectroscopy, conformational analysis, hydrogen bonding and solvent effects, structure and dynamics of weakly bound complexes, transition metal and organic photochemistry, spectroscopy of excited states, ab initio prediction of molecular spectra, and biochemical and astrophysical applications.




Structure Data of Free Polyatomic Molecules


Book Description

This handbook presents structural data on free polyatomic molecules. Since the structure of molecules defines the chemical, physical and biological properties of matter, this information is crucial for understanding, explaining and predicting chemical reactions and biochemical processes, developing new drugs and materials as well as studying interstellar media. Covering the structural data published between 2009 and 2017, this book supplements the previous Landolt–Börnstein volumes “Structure Data of Free Polyatomic Molecules” (eds. K. Kuchitsu, N. Vogt, M. Tanimoto), which included data from the literature published up to 2008. It systematizes and describes peculiarities of molecular structures for about 1000 compounds studied mainly by gas-phase electron diffraction and rotational spectroscopy. All structures are given in three-dimensional representations.




Emergence, Analysis and Evolution of Structures


Book Description

In May 2002 a number of about 20 scientists from various disciplines were invited by the Berlin-Brandenburg Academy of Sciences and Humanities to participate in an interdisciplinary workshop on structures and structure generating processes. The site was the beautiful little castle of Blankensee, south of Berlin. The disciplines represented ranged from mathematics and information theory, over various ?elds of engineering, biochemistry and biology, to the economic and social sciences. All participants presented talks explaining the nature of structures considered in their ?elds and the associated procedures of analysis. It soon became evident that the study of structures is indeed a common c- cern of virtually all disciplines. The motivation as well as the methods of analysis, however, differ considerably. In engineering, the generation of artifacts, such as infrastructures or technological processes, are of primary interest. Frequently, the analysis aims there at de?ning a simpli?ed mathematical model for the optimization of the structures and the structure generating processes. Mathematical or heuristic methods are applied, the latter preferably of the type of biology based evolutionary algorithms. On the other hand, setting up complex technical structures is not pos- ble by such simpli?ed model calculations but requires a different and less model but rather knowledge-based type of approach, using empirical rules rather than formal equations. In biochemistry, interest is frequently focussed on the structures of molecules, such as proteins or ribonucleic acids. Again, optimal structures can usually be de?ned.




Sulphone Molecular Structures


Book Description

Recently, the molecular structures of a relatively large number of sulphone compounds have been elucidated in the vapour phase by electron diffraction and microwave spectroscopy. The main purpose of these studies is the determination of the sulphur bond configuration and the conformational properties. This leads to the observation and correlation of characteristic structural variations as various ligands are attached to the S02 group and as comparisons are made with related molecules. Today it may be said that the structure of sulphone molecules is relatively well studied, and it appeared necessary to systematize the accumulated experimental data after critical considerations. This is done in the first part of this monograph. The second part presents the observed characteristic structural variations. Attempts are made to interpret these variations by valence shell electron pair repulsions and-non-bonded interactions. Correlation relationships between geometric and vibrational parameters are also presented. It is the metrical aspects of the molecular structure which are primarily considered. Since they correlate with other aspects of the molecular structure, e.g. electronic, it is hoped that the experimental information on the molecular geometry provides stim ulus for further experimental, and, in particular, theoretical work on sulphones and related systems. IV It is attempted to cover all electron diffraction and micro wave spectroscopic investigations on sulphone molecules to date. Admittedly, however, relatively larger weight is given to the electron diffraction studies originating from the author's own laboratory.




Transport Coefficients of Fluids


Book Description

In this monograph, the density ?uctuation theory of transport coe?cients of simple and complex liquids is described together with the kinetic theory of liquids, the generic van der Waals equation of state, and the modi?ed free volume theory. The latter two theories are integral parts of the density ?- tuation theory, which enables us to calculate the density and temperature dependence of transport coe?cients of liquids from intermolecular forces. The terms nanoscience and bioscience are the catch phrases currently in fashion in science. It seems that much of the fundamentals remaining unsolved or poorly understood in the science of condensed matter has been overshadowed by the frenzy over the more glamorous disciplines of the former, shunned by novices, and are on the verge of being forgotten. The transport coe?cients of liquids and gases and related thermophysical properties of matter appear to be one such area in the science of macroscopic properties of molecular systems and statisticalmechanicsofcondensedmatter. Evennano-andbiomaterials,h- ever, cannot be fully and appropriately understood without ?rm grounding and foundations in the macroscopic and molecular theories of transport pr- ertiesandrelatedthermophysicalpropertiesofmatterinthecondensedphase. Oneisstilldealingwithsystemsmadeupofnotafewparticlesbutamultitude of them, often too many to count, to call them few-body problems that can be understoodwithoutthehelpofstatisticalmechanicsandmacroscopicphysics. In the density ?uctuation theory of transport coe?cients, the basic approach taken is quite di?erent from the approaches taken in the conventional kinetic theories of gases and liquids.