Ja. Laverne et al., DIFFUSION-KINETIC MODELING OF THE GAMMA-RADIOLYSIS OF LIQUID CYCLOALKANES, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(8), 1997, pp. 1628-1634
A deterministic diffusion-kinetic model has been successfully applied
to the radiation chemistry occurring in a typical spur produced in the
gamma-radiolysis of liquid cyclopentane, cyclohexane, and cyclooctane
. The predictions of the yields of the cycloalkenes, bicycloalkyls, an
d the cycloalkyl iodides in solutions of iodine are in excellent agree
ment with experimental data. The major adjustable parameters in the mo
del are the characteristic radii of the initial Gaussian spatial distr
ibutions of the reactive species. Values for these radii were found to
be 0.5, 1.1, and 0.55 nm in cyclopentane, cyclohexane, and cyclooctan
e, respectively. The results suggest that the spurs of cyclopentane an
d cyclooctane are very small, ca. one molecular diameter, with resulti
ng large local concentrations of reactants. With cyclohexane, the spur
size is twice as large and the initial local concentrations are an or
der of magnitude smaller. The experimentally observed temporal invaria
nce of the cyclohexyl radical can be explained by competing effects in
the spur evolution. Details and implications of the spur model are di
scussed.