That being said, when there is a three state crossing (for example 76 → 78, 79 at t = 68.8 fs as labeled by the black triangle (▲) in Fig. ), the electronic transition becomes more complicated. Here, after the crossing at (▲), the electronic population becomes P 78 ≈ 0.85 and P 79 ≈ 0.15 (i.e. the wavefunction is a superposition of the CIS states of J = 78, 79).