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Physical Chemistry 3: — Chemical Kinetics — - Christian-Albrechts ...

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7.2 Applications of transition state theory 158<br />

The different factors can be evaluated separately:<br />

Ã<br />

!<br />

‡ <br />

µ 32 µ <br />

+ 2 <br />

2 32<br />

=<br />

(7.51)<br />

( )( 2 )<br />

2 2 <br />

<br />

à !<br />

‡ µ <br />

<br />

8 2 ‡ 2<br />

‡<br />

=<br />

= <br />

2 8 2 2 2 2 2 (7.52)<br />

2<br />

<br />

à !<br />

‡ <br />

1 − exp (− 2 )<br />

=<br />

(7.53)<br />

2<br />

3Y<br />

´i<br />

<br />

à !<br />

‡ <br />

2<br />

<br />

=1<br />

= 4<br />

4 × 1<br />

h<br />

1 − exp<br />

³<br />

− ‡ <br />

(7.54)<br />

Note: The difference between the TST result and experiment can be ascribed (a)<br />

to tunneling and (b) deficiencies of the ab initio PES. Indeed, according to newer ab<br />

initio calculations, the TS is actually slightly bent and the TS parameters differ slightly,<br />

yielding better agreement with experiment. ¥

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