Figure 6. 2D (r,Z) cuts of the PES computed for four dissociation geometries: bridge-to-hollow (A),
bridge-to-hollow-shifted (B), hollow-to-bridge (C) and top-to-hollow (D). Contour lines separate
0.2 eV energy intervals, solid lines are used for E ≥ 0 eV and dashed lines for E < 0 eV. Circles
indicate all the stationary points. The black circles represent the entrance channel barriers for
DirDiss ) and the white circles are 2D saddle-points that are not real first order
dissociation (EbDirDiss ) and the white circles are 2D saddle-points in the 6D space (see text for details). 
The top and the side view sketches of thedirect dissociation barrier geometries are reported next to the corresponding elbow plots.

The files *.dat containing the data points used to interpolate the 2D energy cuts are stored in folder ../Tab07