We compare the results of the semi-classical (SC) and quantum- mechanical (QM) formalisms for angular-momentum changing transitions in Rydberg atom collisions given by Vrinceanu et al , with those of the SC formalism using a modified Monte Carlo realization. We find that this revised SC formalism agrees well with the QM results. This provides further evidence that the rates derived from the QM treatment are appropriate to be used when modelling recombination through Rydberg cascades, an important process in understanding the state of material in the early universe. The rates for ∆ ℓ = ± 1 derived from the QM formalism diverge when integrated to sufficiently large impact parameter, b . Further to the empirical limits to the b integration suggested by Pengelly & Seaton, MNRAS 127 , 165 (1964), we suggest that the fundamental issue causing this divergence in the theory is that it does not fully cater for the finite time taken for such distant collisions to complete.
|Number of pages||13|
|Journal||Journal of Physics B: Atomic, Molecular and Optical Physics|
|Publication status||Published - 11 May 2017|
- quantum mechanics
- semi classical formalisms
- atom collisions
Williams, R. J. R., Guzmán, F., Badnell, N. R., van Hoof, P. A. M., Chatzikos, M., & Ferland, G. J. (2017). Thermodynamically-consistent semi-classical ℓ-changing rates. Journal of Physics B: Atomic, Molecular and Optical Physics, 50(11), . https://doi.org/0.1088/1361-6455/aa6f58