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The new book Molecular Symmetry and Group
Theory by R. L. Carter is comprehensive enough for graduate
students but accessible enough for undergraduates. This readable
text includes a qualitative development of group theory,
with applications to bonding and vibrational spectroscopy as
well as electronic spectroscopy of transition metal complexes.
The introduction to group theory in the first four chapters
neatly interweaves basic arguments needed to solve chemical
problems in inorganic chemistry. Later chapters on vibrational
and electron spectroscopy could be used independently or
with connection to other texts.
The organization of the book makes it possible to
adapt its use for two levels of students, either undergraduate
or graduate (who have not seen group theory). For example,
a qualitative procedure for forming SALCs (symmetry
adapted linear combinations) and writing MO (molecular
orbital) diagrams is outlined in Chapter 4. While this might
provide the depth required of an undergraduate course, it also
serves as a solid basis for the more detailed discussion on
projection operators to generate SALCs in Chapter 5. More
advanced topics such as double groups or F and G matrix
treatment of molecular vibrations, however, are not included.
Carter describes several pedagogically useful techniques
within this text: for example, his worksheet method for
reducing representations. This chartlike organization for
reducing representations is not only useful as a teaching tool but
would help minimize mistakes even for one practiced at
reducing representations. In an analogous fashion, the
projection operator method for generating SALCs is broken down into
a sequence of steps, which are also mapped out in tabular form.
While the focus of the text is to present group
theory without a full mathematical derivation, connections to
the mathematical underpinnings are suggested. These
bridges assume a fair amount of knowledge of linear algebra
(e.g., there is only a brief treatment of matrix multiplication,
block diagonalization, and similarity transforms), but they are
not critical to understanding the book. One of the themes
in Molecular Symmetry and Group Theory is
group-subgroup relationships. Where other texts have left the utility of
group-subgroup relationships to the reader, Carter illustrates the
advantages in several contexts. He illustrates this principle
with a number of examples of using rotational subgroups to
write or reduce representations of high-order groups.
I found valuable explanations in
Molecular Symmetry and Group Theory that are not commonly found in other
textbooks. For example, Carter carefully explains how to
reduce representations that involve imaginary characters or
representations in infinite-order groups
and illustrates
several approaches to obtain SALCs for degenerate
representations. Carter's book is far more approachable than Cotton's
Chemical Applications of Group Theory and more easily adaptable to
an undergraduate course. Carter carefully ties each
discussion to relevant, concrete examples. He provides a fuller
treatment of both group theory and its applications than
George Davidson's Group Theory for Chemists, although
Davidson nicely divides his development into short, concise,
topical chapters. While equally readable, Carter's book follows a
more standard approach than a book such as Symmetry and
Structure, by S. F. A. Kettle (who develops point groups in parallel
with writing SALCs and MO diagrams).
By contrast to almost all the other texts I have
mentioned, I particularly appreciate the careful inclusion of data
throughout Molecular Symmetry and Group
Theory. For example, in writing molecular orbital diagrams, Carter provides the
photoelectron spectra of example molecules and relates the
peaks to the MO diagram. Likewise, the chapter on vibrational
spectroscopy includes both infrared and Raman spectra of
compounds discussed. Finally, in the chapter on electronic
spectroscopy, UV-vis absorption spectra are illustrated for the
d1-d9 metals. Excellent problems accompany each chapter.
In terms of coverage and depth,
Molecular Symmetry and Group Theory is well suited to an introductory group
theory course. Although I would unbraid some of the arguments
in the early chapters (particularly for an undergraduate course),
on the whole I found the material very well presented. I
enjoyed reading the book and am likely to adopt it in my own course.
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