Impact parameter centrifugal barrier

Figure 7.7 The effect of rotational energy on the effective potential for a diatomic molecule. The centrifugal barrier is related to the impact parameter for the reverse association reaction. The upper part of the figure shows the dissociation of a rotating diatom (in terms of its reduced mass, p) and the conversion of its angular momentum into orbital angular momentum.

The amount of energy tied up in rotational energy T ot depends on the impact parameter and constitutes a centrifugal barrier,... 

Figure 2.9 A plot of the effective potential for several (increasing) values of the impact parameter. At high b values the well in the potential V F ) is filled in and the effective potential is purely repulsive. The dashed line is the centrifugal barrier alone for the last case.

A plot of Veff( ) versus r at constant E. for several values of the impact parameter is shown in Figure 1 for the collisions of N2 with N2. For the special case in which the centrifugal barrier height equals Ej. (at b= be in Figure 1), E trans( ) = d the particles will... 

Unlike V(R the effective potential shows a maximum at R for each 6, the so-called centrifugal barrier Vz = Eb /Rl,. With the assumption that reaction occurs if E exceeds the centrifugal barrier, the maximum impact parameter b ax ch energy E and hence the reaction cross section (j(E) = nb j, may be calculated. One obtains for this close-collision model (Levine and Bernstein, 1974)... 

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