Minimum energy path of H₂O (lower panel) in eV as a function of r₁ and the second bond length r₂ and the bond angle θ (top panel). The bond length, r₂, is given with the solid line and with values indicated on the left axis, while the bond angle is given with the dashed line with values on the right axis of the top panel. The vertical dashed line represents the position of the global minimum.