Lindemann-Hinshelwood mechanism

How thermal activation can take place following the Lindemann and the Lindemann-Hinshelwood mechanisms. An effective rate constant is found that shows the interplay between collision activation and unimolecular reaction. In the high-pressure limit, the effective rate constant approaches the microcanonical rate... 

Bimolecular steps involving identical species yield correspondingly simpler expressions. A3.4.8.2 THE LINDEMANN-HINSHELWOOD MECHANISM FOR UNIMOLECULAR REACTIONS... 

Figure A3.4.9. Pressure dependence of the effective unimolecular rate constant. Schematic fall-off curve for the Lindemann-Hinshelwood mechanism. A is the (constant) high-pressure limit of the effective rate constant...

We have calculated the addition channel rate constant using the RRKM approach to unimolecular reaction rate theory, as formulated by Troe ( ) to match RRKM results with a simpler computational approach. The pressure dependence of the addition reaction (1) can be simply decribed by a Lindemann-Hinshelwood mechanism, written most conveniently in the direction of decomposition of the stable adduct ... 

Let us assume that a reaction on a surface follows the Lindemann-Hinshelwood mechanism... 

More detailed theories, as described in the following sections, take into account that in reality the rate coefficients of the Lindemann-Hinshelwood mechanism are averages over the quantum states of AB, AB, A, and B. For... 

Note The Lindemann mechanism was also suggested independently by Christiansen. Hence, it is also sometimes referred to as the Lindemann-Christiansen mechanism. The theory of unimolecular reactions was further developed by Hinshelwood and refined by Rice, Rampsberger, Kassel and Marcus. 

The LINDEMANN-HINSHELWOOD theory for unimolecular reactions is based on the following mechanism ... 

In terms of a simple Hinshelwood - Lindemann type mechanism this would be... 

The correct treatment of the mechanism (equation (A3.4.25), equation (A3.4.26) and equation (A3.4.27), which goes back to Lindemann [18] and Hinshelwood [19], also describes the pressure dependence of the effective rate constant in the low-pressure limit ([M] < [CHoNC], see section A3.4.8.2). 

The same result is traditionally derived from the high-pressure limit of the Hinshelwood-Lindemann mechanism see Section 7.4.1. 

The activation and its interplay with chemical reaction is often described by the so-called (generalized) Hinshelwood Lindemann mechanism ... 

When 8 is sufficiently high, every energised molecule A is essentially an activated species A, but this conditions depends on the value of s as shown in Figure 8.4. Figure 8.5 illustrates the apphcation of Lindemann-Christiansen-Hinshelwood, RRK mechanisms to the isomerisation of cyclopropane as a function of pressure [4]. 

---