ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
A point-continuum model for evaluating atom–cluster interaction potentials is developed and applied to the calculation of capture cross sections and thermal association rate constants for atom–cluster association in the framework of the Langevin model. The approach is illustrated by treating the initial capture step in the association reaction of an iodine atom and iodine-doped van der Waals cluster I+I(Ar)n→I2+n Ar. Two cluster sizes n=12 and 54 are considered. The cluster structures correspond to an initial icosahedral geometry of Ar atoms surrounding a central I impurity, denoted Ar6(I)Ar6, and Ar27(I)Ar27 for n=12 and 54, respectively. For I+Ar6(I)Ar6 at lower relative translational energies, Langevin capture cross sections predicted by the point-continuum model agree with classical trajectory results within statistical uncertainty. However, as the relative translational energy increases, the predicted capture cross sections start to deviate slightly from the classical trajectory values. For the larger cluster size (n=54), the predicted capture cross sections and collisional rate coefficient are in quantitative agreement with the predictions of classical trajectory simulation, illustrating the emergence of bulk-like continuum behavior as cluster size is increased.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.465228
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