摘要:

AbstractHundred years ago physical chemistry was mainly concerned with equilibrium properties of macroscopic systems of matter. Energy and entropy were the basic concepts underlying various applications of the laws of thermodynamics. Particle physics and cosmology of our times have uncovered the limits of our understanding of these basic concepts. We had to learn “how strange the universe” is, before we may realize “how simple it is” (J.A. Wheeler, 1973). Physical chemistry of our days is increasingly dealing with material self‐organization far from equilibrium. A new concept is that of molecular storage and processing of information. This concept provides a physico‐chemical understanding of living matter. The paper describes necessary and sufficient conditions for generating information in molecular systems. The theoretical results are confronted with experimental findings obtainedin vitr

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981103

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractStructure and activity of solids and their physico‐chemical interpretation are the subject matter of this overview. After sketching briefly the history of the development of the physical chemistry of solids, solid state kinetics in particular is treated here. Examples are given which show how physico‐chemical concepts influence technologies that are responsible for many aspects of modern civilization. We discuss in particular (1) Point defect thermodynamics and point defect kinetics as the basis of amplifying devices. (2) Diffusional transport in crystals as the basis of solid state reactions and the formation of modern materials and tools. (3) The influence of the elastic potential on solid state kinetics and (4) Morphological stability and its influence on the course of solid state reacti

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981104

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractPhysical chemistry appears on the surface to be an abstract science having only little direct relation to the chemical industry. On closer examination, however, it is very soon apparent that the laws developed within the field of physical chemistry to describe mass systems and mass transformation, as well as energy transfer and energy conversion, are of fundamental importance particularly to industrial chemistry. The application of these laws permits the theoretical treatment and elaboration of chemical processes and thus forms the basis for the realization of these processes on an industrial scale. Thermodynamic and kinetic studies of the chemical reaction are naturally of central importance, but the description of basic operations and measuring systems for process control and safety engineering, too, is only made possible by the application of physico‐chemical laws. This basic role of physical chemistry is described by means of examples from widely differing fields of the chemical industr

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981105

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractA short historical introduction shows a few stations important for the field of theoretical chemistry whose appearance occurred 100 years ago under the term of mathematical physics or mathematical chemistry primarily in the area of physical chemistry. Present possibilities of the field are discussed in a number of examples: today quantumchemical calculations, computer simulations and modelling are a convenient and universally applicable instrument in many areas of chemistry for the interpretation of mechanisms as well as for quantitative prediction.

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981106

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractWe present a review of historical methods in spectroscopy culminating in modern techniques made available by the advent of laser technology. Spectroscopy is undergoing a worldwide renaissance as a result of these methods which point to entire new fields of application. Special examples are given, such as mass spectrometry, very high resolution methods, photoelectron spectroscopy and ZEKE spectroscopy as well as modern ultrafast techniques.

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981107

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractMany of the founders of modern gas phase reaction kinetics were members of the Deutsche Bunsengesellschaft für Physikalische Chemie (the former Deutsche Elektrochemische Gesellschaft). The evolution of this field from its beginnings around 1894 towards today, from qualitative understanding to quantitative modelling is reviewed. The connection between global mechanisms and elementary reaction steps is exemplified by sensitivity tests. Elementary reaction rates then are related to potential energy surfaces showing intermediate energy maxima, i.e. single activated complexes, or intermediate energy minima, i.e. involving several activated complexes

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981108

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractChemical processes at solid surfaces form the basis for heterogeneous catalysis whose scientific investigation and industrial application were initiated at the beginning of this century. Despite early formulation of significant concepts, studies of the elementary steps on atomic scale started only during the past few decades in parallel to the development of powerful experimental tools. The present status will be illustrated by means of selected examples.

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981109

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractThe last decades have witnessed a remarkable change in electrochemistry: from a macroscopic, thermodynamicsoriented approach towards electrochemical problems to a microscopic, atomistic one. The latter was frequently inspired by models derived for the solid‐vacuum interface. The desire and the necessity to understand electrochemical processes on an atomic or molecular level called for new experimental and theoretical routes. Significant advances in the understanding of electrode reactions resulted from the availability of new techniques in electrochemistry, e.g., by adoption of structure‐sensitive surface‐physics techniques to electrochemical needs. Similarly important was the use of single‐crystal electrodes with well‐characterized surfaces. It was their wide‐spread use which brought to light the importance of the surface structure in electrochemical kinetics. In the following we shall demonstrate with a few selected examples how much information about the microscopic structure of electrode surfaces is nowadays available. In this respect, scanning tunneling microscopy has had a major impact. Finally, future trends in fundamental electrochemical research ar

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981110

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractThe lecture begins by reviewing some facts that were already known in colloid science of hundred years ago. The importance of colloid science for the development of human civilization and modern technology is then outlined. The main part of the lecture deals with surfactant science, a subdivision of colloid science:Amphiphilic molecules can assemble in aqueous solution into a variety of micellar structures such as globules, rods, disks and vesicles. For a given system the micellar structures are determined by the packing parameter of the surfactant which controls the spontaneous curvature of a micellar interface. The spontaneous curvature of micelles can be varied continuously by the addition of cosurfactant to the micellar solution. With increasing mole fractionXcof the cosurfactant, the system develops then from micelles with interfaces that are strongly curved around the micellar core over planar interfaces towards interfaces that are curved away from the micellar core. Results are presented for the ternary systems of alkyldimethylaminoxides, n‐alcohols and water. As a consequence of the change of the spontaneous curvatures withXcthe systems undergo several macroscopic phase transitions in dilute solutions. In total eleven different single and multiphase situations are observed when one passes from the dilute surfactant to the dilute cosurfactant solution. The single phase regions are the micellar L1‐phase, two different lamellar liquid crystalline Lα‐phases (Lα1and Lαh) and the isotropic L3or sponge phase. The microstructures of the various phases are identified by electronmicrographs which were obtained with the freeze fracture method. The macroscopic properties of the phases are discussed on the basis of their microstructures. The influence of charges by ionic surfactants on the structures and properties of the mesophase is determined. It is found that the Lαhand the L3‐phase are transformed into a phase with multilamellar vesicles. This phase has a Theological yield stress value and can be used as a particle suspending fluid. The influence of excess salt on the microstructures and the properties of the charged phases is determined.Some of the observed phases show bright colours when illuminated with white light. Some of the phases show colour effects when viewed through crossed

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981111

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY

摘要:

AbstractIntensive studies at both, academic and industrial, laboratories have led to a much better understanding of the relationships between structure/morphology and properties of synthetic polymers. Hence, it became possible in many cases to predict what structures and/or morphologies macromolecules should have in order to meet certain property requirements. This will be demonstrated with four examples: Temperature resistant polymers, alternating copolymers, polymers with liquid crystalline main chains, and highly ordered polymers with nonlinear optical properties.

ISSN:0005-9021    

DOI:10.1002/bbpc.19940981112

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1994

数据来源: WILEY