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Fig. 8

image

Departure coefficients bi of the 4He (full lines) and the 3He levels (dotted lines) as a function of optical depth for a model with ε(4He) = 0.008 and ε(3He) = 0.002. Level designations or principal quantum numbers n of the levels are indicated. The dots mark the run of the He ii ground-state departure coefficient.

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