Hyperfine structure in the B-X transition in I₂

This example reproduces figure 2 from S. Churassy, G. Grenet, M. L. Gaillard and R. Bacis, Opt. Comm. 30 41 (1979), and shows hyperfine structure in the 12-0 band of the B-X electronic transition of I₂. This shows how to handle hyperfine structure for equivalent nuclei; each nucleus should show in the constants tree, but AsNext is set true for the first nucleus it is treated as equivalent to the second and all the constants are taken from the second nucleus. As the hyperfine structure is being explicitly simulated, the statistical weights are set to 1.
If you don't want the hyperfine structure, set nNuclei to 0, and SymWt = 5, AsymWt = 7 for the correct statistical weights.