Biomedical Engineering Reference
In-Depth Information
There are also points where the molecular potential energy is a maximum. We are rarely
interested in these.
Figure 5.3 shows a saddle point (for the function
f
(
x
,
y
)
=
−
y
2
). The vertical axis
shows the function values, and the two horizontal axes are
x
and
y
. The apocryphal reason
why such points are called saddle points is that the figure above resembles a horse's saddle.
Molecular potential energy surfaces generally contain all possible features and you might
like to consider the example shown in Figure 5.4, which shows two (equal) minima and a
saddle point in between.
x
2
Figure 5.3
Saddle point
Figure 5.4
Two minima and a saddle point
