Determination Of Liquid Water Structure Coordination Numbers For Ions And Solvation For Biological Molecules

One should distinguish between coordination numbers and hydration numbers. Following Bockris

This compendium presents some of the major applications of neutron scattering techniques to problems in biology. It is a record of the papers presented at the Neutrons in Biology Conference, the third in an occasional series held to highlight progress in the field and to provide a focus for future direction. The strength ofthe neutron scattering technique remains principally in the manipula tion of scattering density through hydrogen and deuterium atoms. The development ofad vanced detectors, innovative instrument and beamline components, and sophisticated data acquisition systems through the 1970s and early 1980s provided a sound foundation for the technique. With continued development, some of the exotic and expensive equipment has become affordable by the medium-sized facilities, thereby broadening the user base considerably. Despite problems with the major neutron sources in the late 1980s and early 1990s, some spectacular results have been achieved. Whilst the high and medium flux beam reac tors will continue to make a major impact in the field, the results from the first experi ments, and the planned developments on spallation neutron sources, clearly indicate that the technique has enormous potential.

This book was undertaken for the purpose of bringing together the widely diverse lines of experimental work and thinking which has been expressed but has often been unheard on the title question. It will be clear to the reader that a critical viewpoint has been maintained in assembling the material of this rapidly expanding area of concern to organic chemists. It should be clear, too, that the authors are not purvey ing a singular viewpoint and do not regard the discussions presented as the ultimate word on the subject. In fact, it should be anticipated that many ofthe viewpoints pre sented may have to be altered in the light of new developments. In recognition of this and to show the wayan appendix of recent results and interpretation has been included where an alteration in viewpoint on some of the material treated in the text has been necessitated by developments in the most recent literature. This ap pendix should be regarded as the reader's opportunity to maintain currency in all aspects of this subject ifit is kept abreast of the literature. The bibliography, from which most of the material of discussion has been drawn, is organized in a somewhat unusual manner which deserves some explana tion here. A reference citation can consist of (as much as) a six space combination of letters and numerals.

The Advanced Research Workshop entitled “Weakly Interacting Molecular Pairs: Unconventional Absorbers of Radiation in the At- sphere” was held in Abbaye de Fontevraud, France, from April 29 to May 3, 2002. The meeting involved 40 researchers from 14 countries. The goal of this meeting was to address a problem that the scienti?c community is aware of for many years. Up now, however, the so- tion for this problem is far from satisfactory. Pair e?ects are called unconventional in the title of this meeting. In speci?c spectral domains and/or geophysical conditions they are recognized to play a dominant role in the absorption/emission properties of the atmosphere. Water vapor continuum absorption is among the most prominent examples. Permanently improving accuracy of both laboratory studies and ?eld observations requires better knowledge of the spectroscopic features - tributable to molecular pairs which may form at equilibrium. The Workshop was targeted both to clarify the pending questions and, as far as feasible, to trace the path to possible answers since the underlying phenomena are yet incompletely understood and since a reliable theory is often not available. On the other hand, the lack of precise laboratory data on bimolecular absorption is often precluding the construction of reliable theoretical models. Ideally, the knowledge accumulated in the course of laboratory studies should correlate with the practical demands from those who are carrying out atmospheric ?eld measurements and space observations.

Although studies on synthetic dyes have been performed for more than 100 years, their detailed elucidation requires further extensive research. The discovery of novel high polymers, the necessity of supplying a whole range of shades and increasing require ments for dyestuffs of high fastness properties give rise to a permanent search for new dyes. Extensive investigations on dyes were also occasioned by various applications in the field of spectral sensitization and of staining of biological specimens. Another more recent development concerns the lasing properties of some organic dyes. Most of the progress, however, was only achieved by time-consuming, purely empirical approaches and theoretical understanding of the dye properties is only at its very beginnings. The color is the sine qua non of every dye. For this reason organic chemists and color chemists have looked for relations between the "color and constitution" of dye molecules for a long time. This knowlege as a whole is known as "theory of color". The classic theory of color was established abou t 100 years ago by Witt and was signi ficantly extended 50 years later by W. Konig.

Our understanding of elementary processes in plasmas has been increasing dramatically over the last few years. The development of various swarm techniques, such as the temperature variable selected ion flow tube or the selected ion flow drift tube, has provided the prerequisite for detailed investigations into ion molecule reactions both in binary and three body collisions, and the mechanisms of many reactions are now understood quite satisfactorily. This information could not have been obtained without a detailed knowledge of the transport phenomena involved. Some of these, such as the internal-energy distribution of drifting ions, have only very recently been tackled both theoretically and experimentally; a consistent model is now being developed. As the interactions between the various branches of swarm research have become more and more intense, the most obvious thing to do was putting together a review on the present state of this subject, which is the aim of this book.

Charge transport through the transfer of protons between molecules has long been recognized as a fundamental process, which plays an important role in many chemical reactions. In particular, proton transfer through Hydrogen (H-) bonds has been identified as the main mechanism, via which many bio logical functions are performed and many properties of such basic substances as proteins and ice can be understood. In this volume, several of these important aspects of the H-bond are rep resented. As the division in different sections already indicates, present day research in proton teansfer in biochemistry, biology, and the physics of water and ice remains highly active and very exciting. Nearly a decade ago, a novel approach to the study of collective proton motion in H-bonded systems was proposed, in which this phenomenon was explained by the propagation of certain coherent structures called solitons. In the years that followed, the approach ofsoliton dynamics was further extended and developed by many researchers around the world, into a legitimate and useful method for the analysis of proton transfer in H-bonded systems. Dr. Stephanos Pnevmatikos, the original Director of this ARW, was one of the pioneers in the application ofsoliton ideas to the study ofcharge transport through H-bonds. Having used similar concepts himself in his research on 2D lattices) he was convinced energy transfer through molecular chains (and that solitons can play an important role in enhancing our understanding of protonic conductivity.