Figure 3: The relevant first excited state of the dication for deprotonation.
From: Subfemtosecond steering of hydrocarbon deprotonation through superposition of vibrational modes
The state (A3Πu) is shown as a 2D-surface plotted against the symmetric and anti-symmetric stretching coordinates. The arrows in a and b indicate the two directions, into which protons can be emitted. To illustrate the control process, we plotted two wave packets representing the ideal superposition of 
(a) and 
(b). The initial wave packets are shown by white topographic lines, a snapshot of the same wave packet after 2.4 fs in magenta. The negative superposition (a) yields dominant cleavage of the left C-H bond, while the positive superposition (b) yields dominant cleavage of the right C-H bond.
