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Book Review Low Energy Electrons and Surface Chemistry. By G. Ertl and J. Kppers

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nating current circuits, selected topics in magnetostatics,
some of the fundamentals of quantum mechanics and linear algebra, and into the mathematics of exponential operators.
However, accuracy sometimes becomes lost in the authors’ enthusiasm for the subject. Thus, for example, they
talk about “decoupling of differential equations,” where
what they actually mean are linear first-order differential
equations. A more bizarre example is seen on p. 21, where
the symbol t is used with two different meanings within
the same simple equation. The misprint demon has struck
in a particularly malicious way on p. 167, where, as a result
of a “0” (zero) having been converted into the letter “0”,
the whole thing has turned into a hopeless mess.
In a sense the impression is conveyed that the book has
been compiled in such a way as to make it superfluous for
a student working on solid state NMR spectroscopy to
study any other text. The essential problem of the book is,
though, that it is addressed to a fictitious readership.
At the beginning of Chapter 5, on p. 198 (of a total of
275 pages), the authors state that all that has gone previously is only a preparation for the real objective, which is
to understand the mechanism of multipulse cycles. I am
sorry to have to say, though, that the heyday of multipulse
cycles took place ten years ago. Throughout the world
there are now only a few groups working in this particular
field and their number is decreasing rather than growing.
Gerstein and Dybowski mainly ignore the successes of the
multipulse technique, which in my view are best seen in
single crystal studies. It thus seems an ironic accident that
in the one example relating to single crystal measurements,
data containing systematic errors are used. It is casually
stated that in any case most samples are in the form of
powders. The hope is expressed that a combination of
multipulse cycles with rapid rotation of the sample about
the “magic angle” (here dealt with only briefly) will yield a
method equivalent in information content and ease of interpretation to true high resolution liquid state NMR spectroscopy, which is so outstandingly successful as an analytical technique. However, one hardly finds in this volume
any convincing example to support such a hope.
The final chapter is devoted to heteronuclear pulse experiments. The style here is different. We no longer have
detailed analyses and a complete understanding, but instead a more or less traditional presentation of well-known
techniques. It is clearly apparent that the authors are here
no longer drawing on their own store of experience and
knowledge to the extent that they are in the earlier chapters.
The literature citations are a peculiar feature of the
book. On the grounds that this is a textbook, Gerstein and
Dybowski avoid citing original papers so far as possible. In
some places, however, original work is deliberately cited.
The reader may easily guess at the system which is used.
Writing a whole chapter on multipulse cycles and homonuclear pulse experiments in solids without mentioning the
name of J . S . Waugh even once in the text, is, to say the
least, a strange thing-and this is by no means an isolated
example.
Research libraries concerned about full coverage will
not be able to avoid buying this book, but I fear that there
will not be many students, at least in Germany who will
give themselves the “pleasure” of studying it systernatically.
U . Hueberlen [NB 801 IE]
Max-Planck-Institut fur medizinische Forschung,
Heidelberg (FRG)
1054
Low Energy Electrons and Surface Chemistry. By G. Ertl
and J. Kiippers. VCH Verlagsgesellschaft, Weinheim
1986. XII, 374 pp., hard cover, DM 168.00.--ISBN 3527-26056-0
If Irving Langmuir were to appear again on the scene in
surface science he would be captivated by many things, not
the least important of which is the ability we now have of
being able to probe the composition and structure of solid
surfaces with great dexterity and precision. To test the theory of monolayer saturation in adsorption, proposed by
Langmuir, it was necessary to use high-area solids, typically activated charcoal or silica gel which have areas ranging from 20 to 400 m2 g-’. Only by boosting the extent of
the adsorbed phase in this way was it possible to cope experimentally with the reliable measurement of adsorption
from the gas phase or solution. Nowadays, however, it is
routinely possible to monitor the build-up of monolayer
volumes, Vm, from fractions of coverage of 1 0 - ~to unity
when the surface area is no more than a few cmz g - ‘ . The
principal cause of the revolutionary advance has been the
use of electron, and other beams (including soft X-rays,
and ions of light elements) as primary probes for arriving
at the composition, stoichiometry and structure of two dimensional ordered o r disordered two-dimensional structures at solid surfaces. Low-energy monoenergetic electrons (1 to 5 ev) beams are ideal for exciting the vibrations
of chemisorbed and physically adsorbed layers; and from
the diffraction of monoenergetic electrons of energy in the
range 60 to 300 eV, a great deal can be inferred about the
atomic disposition of the exterior surface of a bulk solid
and of overlayers that can form upon it.
It would be difficult to overemphasize the importance of
the study of such systems: they are deeply implicated in
the phenomenology of catalysis, corrosion, epitaxy, and
the vast ramifying technologies that hinge upon these including the fashioning of new devices from quantum well
lasers to fast transistors. At the fundamental level, too, a
great deal needs to be learned about the basics of surface
science. Why does the sticking coefficient of a given gaseous species vary so enormously from one crystal face to
another on a simple solid such as tungsten. For graphite,
for example, the ‘anisotropy’ in sticking coefficient of oxygen as between the prismatic and basal faces is a factor of
some 10”.
In the last two decades major progress has been accomplished in enlarging our understanding and control of the
properties of surfaces. There have been dramatic improvements ever since the first edition of this very fine monograph appeared in 1974. The reader is given concise, expert guidance in numerous facets of surface science, and,
in particular, is introduced to all the principal ways in
which the strong interaction of electrons with matter are
turned to good advantage in gaining further insights into
surface properties and behavior. Only a fastidious concern
for perfection leads one to discover minor almost trivial,
faults with this book. The reviewer is a little disappointed
(and perhaps a few students who will read this text avidly,
will be too) that a more specific definition of work function (introduced on page 101) is not spelled out. The work
function is a notion that often causes confusion for those
that encounter the surface properties of solids for the first
time. A minor omission is a detailed discussion of lowresolution, high-energy electron energy loss spectroscopy
which is currently finding increasing relevance as a tool in
the science of catalysts. But this is understandable if the
title is to be interpreted literally.
The book is lavishly illustrated with the important points
Angew. Chem. Int
Ed Engl. 26 (1987) No. I0
of theory, experiment and, where appropriate, instrumentation is thoroughly discussed. It is moreover, up-to-date,
as evidenced by the treatments of topics as fast-moving
and disparate as inverse photoemission, Auger neutralization and extended- and near-edge X-ray absorption fine
structure.
Drs. Ertl and Kiippers are to be complimented on producing an excellent monograph, the lifetime of which
should, on present trends, substantially exceed that of the
first edition.
John M . Thomas [NB 849 IE]
The Royal Institution, London
Gaseous Ion Chemistry and Mass Spectrometry. Edited by
J. H. Futrell. Wiley, Chichester 1986. xii, 335 pp., bound,
L 57.50.-1SBN 0-471-82803-3
A workshop, from which this book takes its title, took
place in 1983, organized by the Department of Chemistry
of the University of Utah along the lines of a Gordon Conference. The participants wished to put the contributions
on record by publishing a book, lest the matters discussed
should be forgotten. However, it is open to doubt whether
that was a useful aim, and whether it has been achieved.
The papers, written by scientists who in some cases are
of the first rank in their fields, cover thirteen topics, and
are arranged under four groups. They vary greatly in their
length, content, presentation, and coverage of literature for
further study. Some of the papers, such as that by Futrell
on ion cyclotron resonance ( 1 1 pages with 23 references),
are concise but informative; on the other hand some are
quite weak, such as those by Morrison on photoionization
and multiphoton ionization ( 1 I pp., 33 refs.), and on instrumentation (18 pp., 35 refs.). The paper on clusters
by Castleman and Mark (44 pp., 160 refs.) is well worth
reading, and also has the advantage that the bibliography is up-to-date, although it is marred by too much
emphasis on the authors’ own published work, and
insufficient coverage of important contributions from
other groups. In fact it seems to be a general shortcoming of the book that the attention given to papers from
other research groups is inadequate and unduly selective. Considering the level of competence and the high
standing of the authors, one might have expected a
more balanced presentation of the various topics. Two
examples may suffice to illustrate this: in the treatment
of doubly charged cations there is not a word about
Beynon’s charge-stripping experiments, and in the discussion of laser-induced fluorescence in ions one looks
in vain for a reference to the work of J . P. Maier and
collaborators.
All the authors are either physicists or physical chemists,
with only one exception ( D . C. Smith, who contributes a
chapter on biochemical applications which is inappropriate for this book, and is also too superficial). I a m
afraid that the book will not appeal to chemists, and it
would have been more appropriate if the title had mentioned ion physics rather than ion chemistry. It is doubtful
whether students of chemistry or physics will be able to
follow the text easily without some guidance, and since the
specialists have access to other sources of information, I
fear that the effort expended on this book will turn out to
have been in vain.
Helmut Schwarz [NB 843 IE]
Institut fur Organische Chemie
der Technischen Universitat Berlin (FRG)
Angew Chem Inr Ed Engl 26 (1987) No I0
Mikrobiologische und biochernische Verfahrenstechnik; eine
Einfuhrung. By A . Einsele, W . Samhaber, and R . K .
Finn. VCH Verlagsgesellsc‘haft, Weinheim 1985. x, 248
pp., bound, DM 88.00.-ISBN 3-527-261 17-6
The appearance of this book constitutes a highlight in
German scientific literature. The authors have succeeded
in drawing together the interdisciplinary character of biotechnology into a single textbook. The book is in eight
chapters. After an introduction to microbiology and a survey of microbial processes, we reach the subject of the kinetics of such processes. The chapters o n “Mass transfer in
biological systems”, “Sterilization”, “Bioreactors” and
“Process control” lay the foundations for the technology
of these processes, by enabling the reader to understand
the process engineering principles which are followed by
the discussion of Downstream processing.
Each chapter is a complete unit in itself, so that the
reader, depending on his interests and previous knowledge, can concentrate on individual topics, without being
tied to a particular sequence. Readers already familiar
with microbiology will skip the first three chapters, as
these provide a short introduction to the topics of metabolization and regulation, and classify microbial processes
so as to illustrate the many possibilities offered by microorganisms. From their complex nutritional requirements
and the main growth-determining factors we come to the
determination of biomass. This section on the kinetics of
biological processes concludes with the kinetic description
of a batch and a continuous culture.
The supply of oxygen plays a key role in bioreactors,
and the fourth chapter therefore deals with mass transfer.
The fundamental aspects are the solubility of oxygen in
water (Henry’s law), and the oxygen transport coefficient
K,a; three methods for calculating the latter are described,
with their advantages and disadvantages. The theoretical
relationships are explained by means of several examples.
The effects of other hindrances to transport, such as cell
agglomerates, biofilms, and the rheological properties of
the system, are also considered.
The excursion into sterilization which follows is comparatively brief; besides two examples of calculations it covers
continuous steam sterilizing and sterilization of gases.
Much space is given to the bioreactor and techniques of
measurement and control. The reader has to work through
a good 100 pages on the aeration, mixing and oxygen
transfer rates, and on the more important of the dimensionless numbers (e.g. the Newton number). This is followed by other reactor systems, problems of scaling up the
process, and the uses of special-types of reactors (carrier
immobilization, animal cell culture). The essential peripheral devices such as sensors, gas probes, enzyme electrodes, analytical instruments, and the introduction of computers, which are covered under process control technology, are absolutely essential for monitoring the complex
reactions occurring in the fermenter. There is a particularly
detailed examination of the types of electrodes. Downstream processing in biotechnology is a topic large enough
to justify a textbook by itself; consequently in the final
chapter here only general considerations and the principles of the methods can be given. Certain unit operations
are common to the various work-up processes used, e.g.
the separation of solids from liquids as a first step. Filtration methods are central to this topic, as they have recently
undergone much development. The book describes the potential applications of these and the difficulties. Sedimentation, centrifugation and chromatographic separation are
also discussed.
1055
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