Barrier curvature parameter

Barrier curvature parameter. Dots experimentai data crosses curvature of the inner barrier line caicuiated curvature of the iiquid drop barrier inserts representative barrier shapes for an actinide and a transactinide nucieus... 

Here hcofis the barrier curvature parameter and the number of barrier assaults, = 2.5 x 10 ° O Figure 19.14 shows the experimental barrier curvatures plotted against tbe fissiiity parameter. The liquid drop barrier (Nix 1967) is indicated as aline. Tbe actinides show weakly curved thick liquid-drop dominated barriers with a curvature of 0.5 MeV. The transactinide barriers have curvatures close to 1 MeV, compatible with the curvature of the inner barrier measured for the light actinides (Bjornholm and Lynn 1980). 

For each value of the curvature parameter a one finds a critical zone width Kcr, at which nucleation by the polymorphic mode becomes possible. We define this critical width by postulating that the nucleation barrier becomes lower than bOke for all fC > Kci a) (nucleation allowed). No direct measurements of the curvature of the Gibbs potential of the AI9C02 phase are known. Therefore, we first determine... 

The commonest form of general potential function is one in which the Morse potential of BC, corresponding to V with A infinitely separated from BC, is converted smoothly along the reaction path to the Morse potential for AB [318, 305, 319, 298]. The inclusion of adjustable parameters allows systematic changes to be made in the position of the potential barrier (or col) on the surface, the curvature of the path passing from reactants with minimum energy, and the steepness of the potential along this reaction path. 

Figure 7.28 The Eckart barrier. The three parameters are Vp/ arid the curvature expressed as the imaginary (critical) vibrational frequency, v. The zero-point energy in the reaction coordinate must be taken into account. E H) and EJD) are the activation energies for normal and deuterated samples for the case of an H-atom transfer reaction.

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