Van der Waals Forces and Shielding Effects

Van der Waals Forces and Shielding Effects

... 978-3-642-66176-1 DOI: 10.1007/978-3-642-66,176-1 Library of Congress
Cataloging in Publication Data: Rummens, Frans H A 1933 – Van der Waals
forces in NMR intermolecular shielding effects. (NMR basic principles and
progress; v.

Author: Frans H.A. Rummens

Publisher: Springer Science & Business Media

ISBN: 9783642661761

Category: Science

Page: 122

View: 523

The usefulness of solvent effect studies on NMR chemical shifts need not be elabo rated here; many applications of solvent effects continue to be published in great profusion. Quite a few intermolecular phenomenae may contribute to solvent shifts, but there is always the ubiquitous Van der Waals effect ow. Contrary to such other effects as neighbour anisotropy 0a, reaction field contribution 0E or complexation effects 0e, no major direct use has yet been found for the Van der Waals effect. So far the role of the Van der Waals effect has been that of a nasty, disturbing phenom enon, something to be eliminated at all costs. But it is precisely in this latter respect where almost all solvent effect studies fall short. Not only is Ow usually large (larger than 0a and 0E even in 1 H NMR and probably the dominating term with heavier nuclei), but it is strongly variable from one solute to another and even from one nu clear site to another in the same solute molecule. No referencing technique, however cleverly devised, will be capable of eliminating the Ow contribution from the other, presumedly more interesting contributions. It appeared quite recently that mathematical trickery by the name of "factor analysis" could achieve the sought-for separation of contribuants.
Categories: Science

Chlorine Bromine and Iodine NMR

Chlorine  Bromine and Iodine NMR

10: F. H. A. Rummens Van der Waals Forces and Shielding Effects 13 figures, 46
tables. II, 118 pages. 1975 Contents: Van der Waals Forces in NMR
Intermolecular Shielding Effects: Historical Development (up to 1961). –
Continuum Models.

Author: B. Lindman

Publisher: Springer Science & Business Media

ISBN: 9783642663635

Category: Science

Page: 372

View: 145

The increasing interest in NMR spectroscopy of what in some confer ences in this field is commonly termed "other nuclei" is unmistakable. Chemists and biologists who employ NMR spectroscopy to study their problems have, however, been somewhat reluctant to study nuclei with electric quadrupole moments. These nuclei frequently give rise to broad NMR signals, sometimes too broad to be detectable with ordinary high resolution NMR spectrometers. Spectrometers that could cope with broad NMR signals of low intensity, "wide-line" spectrometers, have been available since the mid 1950:s but it appears that most of these instruments ended up in physical laboratories where the research was primarily directed towards solid state problems. The study of quadrupolar nuclei can provide unique and very valuable information on a variety of physico-chemical and biological systems. For one thing the relaxation of quadrupolar nuclei is in many ways easier to interpret than the relaxation of non-quadrupolar nuclei, since the former is in many cases caused by purely intramolecular interactions modulated by the molecular motion. Studies of quadrupolar relaxation have therefore furnished important information about molec ular reorientation and association in liquids and have played - and will certainly play for many years - an important role in testing new theoretical models of molecular motion in liquids.
Categories: Science

High Resolution NMR Spectroscopy in Solids

High Resolution NMR Spectroscopy in Solids

10: Van der Waals Forces and Shielding Effects 13 figs. 46 tables. II, 118 pages.
1975 Contents: F. H. A. Rummens, Van der Waals Forces in NMR Intermolecular
Shielding Effects: Historical Development (up to 1961). Continuum Models.

Author: M. Mehring

Publisher: Springer Science & Business Media

ISBN: 9783642963322

Category: Science

Page: 248

View: 364

Manipulation and Dilution Tools for Ruling Abundant Species "NMR is dead" was the slogan heard in the late 1960s at least among physicists, until John S. Waugh and his co-workers initiated a series of new NMR experiments, which employed the coherent modulation of interactions by strong radiofrequency fields. A wealth of new phenomena was observed, which are summarized in the introduction for the convenience of the unbiased reader, whereas Section 2 collects the basic spin interactions observed in solids. Line-narrowing effects in dipolar coupled solids by the application of multiple pulse experiments are extensively discussed in Section 3. Numerous extensions of the basic Waugh, Huber, and Haeberlen experiment have been developed by different groups and have been applied to the nuclei IH, 9Be, 19F, 27Al, 31p, 63CU in solids. Application of this technique to a variety of systems is still in progress and should reveal interesting insights into weak spin interactions in solids. It was soon realized that rare spins could be used as monitors for molecular fields in the solid state; however, rare spin observation is difficult because of the small signal-to-noise ratio. Pines, Gibby, and Waugh introduced a new concept of cross-polarization, based on ideas of Hahn and co-workers, which allows the detection ofrare spins with increased sensitivity. The dynamics involved are treated in detail. Other sections merely list results obtained by the techniques described and demonstrate their usefulness in the investigation of dynamical problems in molec ular and solid state physics.
Categories: Science

Physical Properties of Polymers Handbook

Physical Properties of Polymers Handbook

Instead, the effects of substituents and local conformation have been used to
correlate the 13C chemical shifts and the ... that correlate shielding y-effects with
attractive van der Waals forces and not repulsive steric interactions, though their
 ...

Author: James E. Mark

Publisher: Springer Science & Business Media

ISBN: 9780387690025

Category: Technology & Engineering

Page: 1076

View: 577

This book offers concise information on the properties of polymeric materials, particularly those most relevant to physical chemistry and chemical physics. Extensive updates and revisions to each chapter include eleven new chapters on novel polymeric structures, reinforcing phases in polymers, and experiments on single polymer chains. The study of complex materials is highly interdisciplinary, and new findings are scattered among a large selection of scientific and engineering journals. This book brings together data from experts in the different disciplines contributing to the rapidly growing area of polymers and complex materials.
Categories: Technology & Engineering

NMR in Living Systems

NMR in Living Systems

Medium Effects on Nuclear Shielding Interactions between solute and solvent
molecules in a given solution may be treated as ... A general pair interaction
model includes terms due to van der Waals forces, bulk susceptibility effects,
electric ...

Author: T. Axenrod

Publisher: Springer Science & Business Media

ISBN: 9789400945807

Category: Medical

Page: 418

View: 696

In the four decades since its discovery nuclear magnetic resonance (NMR) has become an indispensable tool for obtaining chemical information often. inaccessible by other methods. With the development of instruments of increasingly higher magnetic field strengths, the integration of powerful computers and the availability of an expanding array of flexible software new applications and developments have proliferated rapidly. Among the more exciting new advances is the use of NMR spectroscopy to probe biological systems. The last ten years have witnessed tremendous progress in the development of new NMR imaging and spectroscopic techniques for research and diagnostic applications. The ability to investigate metabolic processes and anatomical structure of intact biological systems under conditions that are totally non-destructive and non-invasive clearly provides much of the impetus for the intense activity that has been generated in the fields of medicine, radiology and the allied basic sciences. Significant advances have been made in this brief period: Whole-body proton NMR imaging today provides anatomical definition of normal and abnormal tissue with a contrast and detection sensitivity often superior to those of X-ray computed tomography and other competing imaging methods. Biochemical pathways, using NMR spectroscopy of protons, carbon-13 and phosphorus-31 nuclei in live animals and man can readily be followed by surface-coil methods to detect metabolites in localized regions. Indicative of the importance and widespread acceptance of these techniques is the explosive growth that the NMR literature is experiencing. This augers well for the future.
Categories: Medical

Aerosol Technology

Aerosol Technology

The main adhesive forces are the van der Waals force, the electrostatic force, and
the force arising from the surface ... Because of the shielding effects of adsorbed
layers of water and organic molecules, chemical bonds are not important for the ...

Author: William C. Hinds

Publisher: John Wiley & Sons

ISBN: 9781118591970

Category: Technology & Engineering

Page: 504

View: 401

The #1 guide to aerosol science and technology -now better than ever Since 1982, Aerosol Technology has been the text of choice among students and professionals who need to acquire a thorough working knowledge of modern aerosol theory and applications. Now revised to reflect the considerable advances that have been made over the past seventeen years across a broad spectrum of aerosol-related application areas - from occupational hygiene and biomedical technology to microelectronics and pollution control -this new edition includes: * A chapter on bioaerosols * New sections on resuspension, transport losses, respiratory deposition models, and fractal characterization of particles * Expanded coverage of atmospheric aerosols, including background aerosols and urban aerosols * A section on the impact of aerosols on global warming and ozone depletion. Aerosol Technology, Second Edition also features dozens of new, fully worked examples drawn from a wide range of industrial and research settings, plus new chapter-end practice problems to help readers master the material quickly.
Categories: Technology & Engineering

Microbial Adhesion to Surfaces

Microbial Adhesion to Surfaces

( i ) Long - range attractive interactions These result from the van der Waals and
electrostatic forces . ... Wim and , since the liquid has a partial shielding effect on
the interaction force , the van der Waals force Fvdw is reduced by the ratio Wim lū
.

Author: R. C. W. Berkeley

Publisher:

ISBN: UOM:39015038942606

Category: Adhesion

Page: 559

View: 275

Categories: Adhesion

Australian Journal of Chemistry

Australian Journal of Chemistry

Abstract A novel van der Waals shielding mechanism is discussed which
contributes to the magnetic shielding non - equivalence of optical ... Rummens , F
. H . A . , ' Van der Waals Forces and Shielding Effects ' ( Springer : Berlin 1975 ) .

Author:

Publisher:

ISBN: UCSC:32106013065351

Category: Chemistry

Page:

View: 817

Categories: Chemistry

13c Nmr Spektroskopie

13c Nmr Spektroskopie

Mason , J . ( 1976 / 1979 ) , Correlations in nuclear magnetic shielding , Adv .
Inorg . Chem . Radiochem . ... Rummens , F . A . H . ( 1975 ) , Van der Waals
forces and shielding effects , in NMR , Basic Principles and Progress , Vol . 10 ,
Springer ...

Author: Hans-Otto Kalinowski

Publisher: Wiley-Blackwell

ISBN: UOM:39015035231649

Category: Science

Page: 776

View: 292

13C NMR spectroscopy has not only become an established and well documented technique, but is about to yield even more detailed information on increasingly complex organic and biological systems, through the possibilities opened by pulse techniques. This work describes these techniques.
Categories: Science

NMR Spectroscopy and Polymer Microstructure

NMR Spectroscopy and Polymer Microstructure

Li and Chestnut ( 1985 ) have presented evidence that correlate shielding y -
effects with attractive van der Waals forces and not repulsive steric interactions ,
though their results still suggest that the gauche arrangement of the observed ...

Author: Alan E. Tonelli

Publisher: Wiley-VCH

ISBN: UOM:39015015178943

Category: Nuclear magnetic resonance spectroscopy

Page: 252

View: 869

Describes both high resolution solution and solid state techniques; presents applications to synthetic and biological polymers; demonstrates the connection between microstructures, conformations, and NMR spectra of polymers. Annotation copyrighted by Book News, Inc., Portland, OR
Categories: Nuclear magnetic resonance spectroscopy

AS Chemistry for AQA

AS Chemistry for AQA

This extra shielding means that the effect of the nuclear charge is reduced , so
the ability of the nucleus to attract electrons is also ... As the molecules get bigger
, the strength of the van der Waals forces between the molecules increases . Fig .

Author: John Atkinson

Publisher: Heinemann

ISBN: 0435581341

Category: Chemistry

Page: 296

View: 361

This chemistry text is written to match exactly the specification for teaching Advanced Chemistry from September 2000. There are two strands, AS and A2, with student books. The accompanying resource packs are also available on CD-ROM.
Categories: Chemistry

NMR at Very High Field

NMR at Very High Field

Thus one may seriously start to consider high resolution NMR at 1 GHz. The purpose of this volume is to examine some of the advantages which can be obtained at such high frequencies and some of the problems we shall be facing.

Author: J.B. Robert

Publisher: Springer

ISBN: 3540529462

Category: Science

Page: 168

View: 642

In recent years several improvements have been made in the manufacturing of resistive, superconducting and hybrid mag nets. Condensed matter physicists are nowadays doing ex periments in steady magnetic fields of up to 30 Tesla. But the field homogenity {/B}, required in a volume of the order of a 3 few cm is usually several orders of magnitude less severe than the one which is needed for high resolution NMR. Over the last 30 years, with each generation of new high resolution NMR spectrometers, from 100 MHz up to 600 MHz, taking advan tage of the increase in sensitivity and resolution, new areas of research have been opened in chemistry, physical chemistry and biochemistry. The generation of the 20 Tesla supercon ducting magnets is coming. Thus one may seriously start to consider high resolution NMR at 1 GHz. The purpose of this volume is to examine some of the advantages which can be obtained at such high frequencies and some of the problems we shall be facing. An important aspect of NMR at high field which is not presented in this volume concerns the design of the magnet. The building of a superconducting magnet, producing a field 10 3 higher than 20 T, with a field homogeneity IlB/B 10- , in a cm volume still remains today in 1990 a major challenge. Grenoble, France J. B. Robert Guest-Editor Professor J. B. Robert Service National des Champs Intenses B. P.
Categories: Science

Nuclear magnetic shielding in methylfluoride at high pressures

Nuclear magnetic shielding in methylfluoride at high pressures

The influence of an axially symmetric molecule 2 on the shielding constant of
molecule l in the configuration t2 , as defined ... 2.4 Exchange effects
Intermolecular forces are usually divided into long - range attractive Van der
Waals forces and ...

Author: Frank Willem Van Emden

Publisher:

ISBN: UCAL:B2704176

Category:

Page:

View: 851

Categories:

Pulsed Laser induced Evaporation of Liquids and Its Applications

Pulsed Laser induced Evaporation of Liquids and Its Applications

The first category includes long range attractive interaction due to the long range
forces such as Van der Waals ( VW ) ... immersion of particles in liquid decreases
Van der Waals and electrostatic adhesion because of the shielding effect .

Author: Dongsik Kim

Publisher:

ISBN: UCAL:C3409699

Category:

Page: 336

View: 942

Categories:

Essential Physics for Manual Medicine E Book

Essential Physics for Manual Medicine E Book

... 181 electromagnetism, 153–4 electron(s) discovery, 127 flow, measurement of,
158 photoelectric effect, 136 spin, 142, ... 137–8, 142–3 energy states, 138
nomenclature, 137 van der Waals bonds, 148 electron shielding, 138 electronics,
 ...

Author: Martin Ferrier Young

Publisher: Elsevier Health Sciences

ISBN: 9780702050022

Category: Medical

Page: 272

View: 906

A textbook that covers Physical concepts at a basic level for manual therapists specifically . Clinicians in general and manual therapists in particular have a need tounderstand certain, specific aspects of physics to an advanced level.However, many lack prior education in this area, with chemistry and biology 'A' levels being emphasized in terms of entrance requirements. Most textbooks aimed at this field concentrate exclusively on the physics underpinning biomechanics, but the level at which these books are pitched is often too high to allow understanding by students who have an inadequate background in the subject. This book acts, in part, as a primer to address this deficit. Students are also required to understand the basic physics underpinning physiology, biochemistry, radiography and therapeutics. This textbook will be a guide to these specialist areas of knowledge. This text will cover biophysics as a core subject to guide the potential clinician from total ignorance to complete mastery in the areas of physics pertinent to manual medicine and its related disciplines.
Categories: Medical

The Pearson Guide to Objective Chemistry for the AIEEE

The Pearson Guide to Objective Chemistry for the AIEEE

CO , is a gas due to weak van der Waals forces . Rest 3 ... decreases
systematically PbBr , and Pbl , do not exist as Br , I are strong due to increase in
their atomic radii and shielding effect . reducing agents and Pb 4 is a strong
oxidizing agent .

Author: Singhal Atul

Publisher: Pearson Education India

ISBN: 8131733815

Category:

Page: 962

View: 450

Categories:

Chemistry and Industry

Chemistry and Industry

He describes in detail the determination of anharmonic force constants for
triatomic molecules and indicates their ... TI Williams N.m.r. basic principles and
progress volume 10 ( van der Waals forces and shielding effects ) 1975 editors P
Diehl ...

Author:

Publisher:

ISBN: UCSD:31822008586927

Category: Chemistry, Technical

Page:

View: 327

Categories: Chemistry, Technical

Subject Catalog

Subject Catalog

Author: Library of Congress

Publisher:

ISBN: WISC:89126008143

Category:

Page:

View: 450

Categories: