Chemistry Reference
In-Depth Information
Statistical
Mechanics
Thermodynamics
Kinetic Theory
Quantum Theory
Absolute Reaction
Rate Theory
Fig. 2.1 The conceptual structure of the absolute reaction rate theory
As this discussion shows, the theory has two aspects of interest to the philoso-
pher of science:
1. The introduction and specification of a special chemical state, the
transition
'
in terms of a specific location on the potential energy surface of the
reaction;
2. The degree to which explanation depends on comparison between the collision,
thermodynamic, and quantum mechanical/statistical mechanical formulations of
molecular quantities.
state
'
Hence, the theory of absolute reaction rates has a complex structure which given
in Fig. 2.1 . The purpose of the theory was to provide exact expressions for the two
constants A and EA . From the viewpoint of quantitative explanations for these
quantities the theory has been moderately successful, but has, in the words of
Laidler and King ( 1983 ),
.
The most interesting aspect of the absolute reaction rate theory is that, again in
the words of Laidler and King, it provided a
its difficulties
'
'
[ ... ] conceptual framework with the aid of which experimental chemists (and others) can
gain some insight into how chemical processes occur. On this score the theory must receive
the highest marks; for nearly half a century it has been a valuable working tool for those
who are not concerned with the calculation of absolute rates but are helped by gaining some
insight into chemical and physical processes. The theory provides both a statistical-
mechanical and a thermodynamic insight - one can take one ' s choice or use both formu-
lations. (Laidler and King 1983 , p. 2664)
In this sense, the theory of absolute reaction rates is a very strong example for the
unity of science - it is precisely one of those examples where it is hard to imagine a
chemistry with the physics removed, but at the same time it is a
chemical
theory in
'
'
that it focuses on molecules, molecular structures, and transformations.
2.4.2 Structuralist Characterisation
I have presented a structuralist characterisation of quantum chemistry in Hettema
( 2012a ) and will, for the purposes of this section, draw extensively on the structur-
alist framework developed there. Since in what follows we will focus on the
changes in conceptual space as outlined by G¨rdenfors and Zenker ( 2011 )we
 
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