Charge transfer and diffusion cross-sections of low-lying excited states are calculated using ab initio quantum-mechanical potential-energy curves. These data are used to calculate the reactive thermal conductivity λR of an atmospheric nitrogen plasma. Differences of up to 20 % are found between the present values of λR and the corresponding values obtained by increasing the cross-sections of excited states by a factor of 2. These differences propagate, to a minor extent (10 %), in the total thermal conductivity.