Close-coupling calculations of Ca- formation by charge transfer from Rydberg atoms - art. no. 022718

We formulate the semiclassical close-coupling method for a theoretical desc ription of ion-pair formation in Rydberg-atom-ground-state-atom collisions at thermal energies and apply it to the process Ca(4s(2)) + Ne*(n) --> Ca- (4s(2)4p) + Ne+. Our results for the formation of an isolated negative-ion state are very close to those obtained previously using the decay model, al though the results for S states are somewhat higher, since the decay model underestimates the survival probability for the ion pair. After the inclusi on in our close-coupling calculations of the two fine-structure components of Ca-, we find that the cross section increases substantially (by about a factor of 2) because of correlation between probabilities for population of two hue-structure sublevels.