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BOOK
REVIEWS
other forms of light emission in t h e first chapter, t h e
s u m m a r y of t h e b a n d t h e o r y of solids as applied to
luminescence in t h e third, a n d t h e t r e a t m e n t of d e c a y
laws of phosphorescence in t h e fourth h a v e considerable
pedagogic value. The survey of t h e history of luminescence in t h e second chapter suffers from an almost exclusive concentration on decay laws of phosphorescence.
I m p o r t a n t topics such as t h e glow-curve w o r k of Urbach,
R a n d a l l & Wilkins, a n d Gaxlick, or t h e chemical concentration studies of the E i n d h o v e n group are omitted.
I n the field of decay curves, however, there is extensive
reference to (and criticism of) the work of others.
The m o r e a d v a n c e d reader will find worth-while
material in t h e chapters on radiationless transitions in
crystal phosphors.
The absence of an index is regrettable.
3. 3. D R O P K I N
Polytechnic Institute of Brooklyn
Brooklyn 1, N.Y., U.S.A.
The Theory of Cohesion. By M. A. JAswo~. Pp.
v i i i + 2 4 5 w i t h 42 figs. L o n d o n : P e r g a m o n P r e s s ;
New York and London: Interscience Publishers.
1954. P r i c e 37s.6d; $5.75.
The a u t h o r has i n t e n d e d this book as an outline of t h e
principal ideas a n d physical concepts u n d e r l y i n g t h e
various approaches to the problems of cohesion r a t h e r
t h a n as a practical guide on t h e detailed application of
a n y one m e t h o d . The emphasis is on pointing out t h e
logical construction of t h e theoretical m e t h o d s a n d on
delineating clearly t h e n a t u r e a n d limitations of t h e
a p p r o x i m a t i o n s involved.
The t h e o r y of c o h e s i o n - - t h e t e r m is used in its m o s t
general sense b y J a s w o n - - d e a l s w i t h t h e d e t e r m i n a t i o n
of t h e stable states, a n d particularly of the energy of t h e
ground state, of m a n y - b o d y systems. Since exact solutions cannot be obtained, t h e m a i n concern of t h e t h e o r y
is t h e construction of suitable procedures of approximation. I n particular, these are developed a r o u n d two m a j o r
problems, namely, t h e interaction b e t w e e n electrons,
a n d t h e m o t i o n of a single electron u n d e r the influence of
m a n y centers of force. The i m p o r t a n c e of these two
problems stems from t h e a t t e m p t to replace t h e exact
forces acting on the electrons during the passage of t i m e
by suitable average interactions of the rest of the system
w i t h i n d e p e n d e n t particles. Clearly, this is most successful
in situations of high s y m m e t r y a n d large n u m b e r of
particles. I n dealing w i t h systems of i n t e r m e d i a t e size
a n d complex structure, as well as in the s t u d y of t h e more
refined properties of t h e m o r e s y m m e t r i c a l systems, such
a p p r o x i m a t i o n s are less satisfactory.
I n order to m a k e t h e book self-contained, t h r e e chapters
on wave mechanics, the h y d r o g e n a t o m a n d p e r t u r b a t i o n
m e t h o d s precede t h e discussion of t h e m a i n topics. T h e
f r a m e w o r k of cohesion t h e o r y is t h e n d e v e l o p e d b y
t r e a t i n g t h o r o u g h l y those simple systems which h a v e
served as the starting point of t h e formulation of its m a i n
concepts. Thus, t h e helium a t o m exemplifies a t o m i c
cohesion. The chapter d e v o t e d to it is concerned at l e n g t h
w i t h the problem of electron interactions, discussing t h e
significance of t h e one-electron a p p r o x i m a t i o n s of t h e
H a r t r e e and H a x t r e e - F o c k equations. I n t h e following
chapter the H + molecule illustrates t h e problem of m a n y
e q u i v a l e n t force centers, a n d s u b s e q u e n t l y b o t h parts of
t h e m a n y - p a r t i c l e problem are combined in t h e t r e a t m e n t
of H~. This leads directly into a critical e x a m i n a t i o n of
t h e physical c o n t e n t of the molecular orbital a n d H e i t l e r L o n d o n approximations, a n d some of t h e r e f i n e m e n t s of
these theories, either b y formal m a t h e m a t i c a l procedure
or by physical a r g u m e n t , axe p o i n t e d out.
I n t e r m s of t h e same concepts two other chapters deal
w i t h the principles of constructing molecular orbitals in
solids, a n d t h e wave functions of co-valent structures.
An additional chapter is concerned entirely w i t h metals,
emphasizing t h e construction of self-consistent oneelectron w a v e functions b y t h e cellular m e t h o d , a n d t h e
i m p o r t a n c e of t h e resulting nearly-free character of t h e
conduction electrons in t h e explanation of metallic
properties. R e f i n e m e n t s of t h e basic approach, which are
n e e d e d to deal w i t h t h e transition metals a n d alloys, are
explained in terms of various specialized approximations.
Here a t t e n t i o n is often d r a w n to m o r e recent contributions, m o s t l y from t h e British literature.
The p r e s e n t a t i o n is v e r y clear and, while concise,
never hurried. T h o u g h mostly qualitative, t h e book gives
a useful survey of the m a t h e m a t i c a l techniques of t h e
m a n y - b o d y problem. The beginning chapters, in particular, contain good explanations of a large n u m b e r of
m i n o r w b u t sometimes troublesome---points arising in
the construction of acceptable wave functions w h i c h are
usually glossed over.
Because of the n a t u r e of its approach, this book should
a t t r a c t a r a t h e r large audience. Workers in m a n y fields
in which n e w e x p e r i m e n t a l t e c h n i q u e s a n d a shift of
emphasis to f u n d a m e n t a l problems h a v e m a d e t h e unders t a n d i n g of cohesion a m a t t e r of considerable interest will
find it an excellent, self-contained i n t r o d u c t i o n n o t requiring very special preparation.
H. JURETSCrrKE
Polytechnic Institute of Brooklyn
Brooklyn 1, N.Y., U.S.A.