Chemistry Reference
In-Depth Information
A robust and contemporary overview of the theory is given in the topic by
Glasstone et al. (
1941
).
The theory of absolute reaction rates was independently developed by Eyring
(
1935
) and Evans and Polanyi (
1935
), and was the subject of heated debate during
the 1930s. In the introduction to the 1937 conference about the theory held at the
University of Manchester, the president of the conference in his address remarked
that the jury on the
theory was still out:
As to whether these methods are fundamentally sound or unsound is a question the
consideration of which belongs rather to the domain of philosophy than to that of chemistry,
and it may be necessary to call in an expert in that branch of science to advise us in the
matter. (Travers
1938
,p.1)
Somewhat belatedly, it is my opinion that the philosophers of science are, at this
point at least, likely to disappoint the scientist, and provide no such advice. Instead,
it is the purpose of this last section to use the theory as an illustration of how the
theory - whether fundamentally sound or unsound - is a good illustration of how a
typical chemical theory functions, and to use it to illustrate the ideas developed in
the previous sections.
'
absolute
'
2.4.1 Overview of the Theory
Glasstone et al. (
1941
) gives a topic-length treatment of the theory. Eyring
et al. (
1944
) discuss the theory in a single chapter, adding a quantum mechanical
formulation of the theory. The historical development of the theory is discussed in
Laidler and King (
1983
) as well as in Miller (
1998
).
Let us now briefly summarise the theory. If we consider a chemical reaction
A
þ
B
þ ...$
C
þ
D
þ ...
ð
2
:
1
Þ
the rate of the reaction is given by Arrhenius law. Arrhenius
'
law is the main
explanatory target of absolute reaction rate theory. Arrhenius
'
law was developed
1889
12
and writes the rate constants k
k
¼
A
exp
ð
E
=
RT
Þ
ð
2
:
2
Þ
expressing the rate constant for a chemical reaction in terms of a
'
frequency
'
factor
A
and an
'
activation
'
energy
E
. Several candidate theories were developed to
explain Arrhenius
law.
One of those candidate theories was the
collision theory
. In this theory, the
'
A
in Arrhenius
'
frequency factor
'
'
equation is interpreted as equal to the frequency
12
The article appears in translated form in Back and Laidler (
1967
).
